MAYBE We are left with following problem, upon which TcT provides the certificate MAYBE. Strict Trs: { fstsplit(0(), x) -> nil() , fstsplit(s(n), nil()) -> nil() , fstsplit(s(n), cons(h, t)) -> cons(h, fstsplit(n, t)) , sndsplit(0(), x) -> x , sndsplit(s(n), nil()) -> nil() , sndsplit(s(n), cons(h, t)) -> sndsplit(n, t) , empty(nil()) -> true() , empty(cons(h, t)) -> false() , leq(0(), m) -> true() , leq(s(n), 0()) -> false() , leq(s(n), s(m)) -> leq(n, m) , length(nil()) -> 0() , length(cons(h, t)) -> s(length(t)) , app(nil(), x) -> x , app(cons(h, t), x) -> cons(h, app(t, x)) , map_f(pid, nil()) -> nil() , map_f(pid, cons(h, t)) -> app(f(pid, h), map_f(pid, t)) , process(store, m) -> if1(store, m, leq(m, length(store))) , if1(store, m, true()) -> if2(store, m, empty(fstsplit(m, store))) , if1(store, m, false()) -> if3(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))) , if2(store, m, false()) -> process(app(map_f(self(), nil()), sndsplit(m, store)), m) , if3(store, m, false()) -> process(sndsplit(m, app(map_f(self(), nil()), store)), m) } Obligation: innermost runtime complexity Answer: MAYBE We add following dependency tuples: Strict DPs: { fstsplit^#(0(), x) -> c_1() , fstsplit^#(s(n), nil()) -> c_2() , fstsplit^#(s(n), cons(h, t)) -> c_3(fstsplit^#(n, t)) , sndsplit^#(0(), x) -> c_4() , sndsplit^#(s(n), nil()) -> c_5() , sndsplit^#(s(n), cons(h, t)) -> c_6(sndsplit^#(n, t)) , empty^#(nil()) -> c_7() , empty^#(cons(h, t)) -> c_8() , leq^#(0(), m) -> c_9() , leq^#(s(n), 0()) -> c_10() , leq^#(s(n), s(m)) -> c_11(leq^#(n, m)) , length^#(nil()) -> c_12() , length^#(cons(h, t)) -> c_13(length^#(t)) , app^#(nil(), x) -> c_14() , app^#(cons(h, t), x) -> c_15(app^#(t, x)) , map_f^#(pid, nil()) -> c_16() , map_f^#(pid, cons(h, t)) -> c_17(app^#(f(pid, h), map_f(pid, t)), map_f^#(pid, t)) , process^#(store, m) -> c_18(if1^#(store, m, leq(m, length(store))), leq^#(m, length(store)), length^#(store)) , if1^#(store, m, true()) -> c_19(if2^#(store, m, empty(fstsplit(m, store))), empty^#(fstsplit(m, store)), fstsplit^#(m, store)) , if1^#(store, m, false()) -> c_20(if3^#(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))), empty^#(fstsplit(m, app(map_f(self(), nil()), store))), fstsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) , if2^#(store, m, false()) -> c_21(process^#(app(map_f(self(), nil()), sndsplit(m, store)), m), app^#(map_f(self(), nil()), sndsplit(m, store)), map_f^#(self(), nil()), sndsplit^#(m, store)) , if3^#(store, m, false()) -> c_22(process^#(sndsplit(m, app(map_f(self(), nil()), store)), m), sndsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) } and mark the set of starting terms. We are left with following problem, upon which TcT provides the certificate MAYBE. Strict DPs: { fstsplit^#(0(), x) -> c_1() , fstsplit^#(s(n), nil()) -> c_2() , fstsplit^#(s(n), cons(h, t)) -> c_3(fstsplit^#(n, t)) , sndsplit^#(0(), x) -> c_4() , sndsplit^#(s(n), nil()) -> c_5() , sndsplit^#(s(n), cons(h, t)) -> c_6(sndsplit^#(n, t)) , empty^#(nil()) -> c_7() , empty^#(cons(h, t)) -> c_8() , leq^#(0(), m) -> c_9() , leq^#(s(n), 0()) -> c_10() , leq^#(s(n), s(m)) -> c_11(leq^#(n, m)) , length^#(nil()) -> c_12() , length^#(cons(h, t)) -> c_13(length^#(t)) , app^#(nil(), x) -> c_14() , app^#(cons(h, t), x) -> c_15(app^#(t, x)) , map_f^#(pid, nil()) -> c_16() , map_f^#(pid, cons(h, t)) -> c_17(app^#(f(pid, h), map_f(pid, t)), map_f^#(pid, t)) , process^#(store, m) -> c_18(if1^#(store, m, leq(m, length(store))), leq^#(m, length(store)), length^#(store)) , if1^#(store, m, true()) -> c_19(if2^#(store, m, empty(fstsplit(m, store))), empty^#(fstsplit(m, store)), fstsplit^#(m, store)) , if1^#(store, m, false()) -> c_20(if3^#(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))), empty^#(fstsplit(m, app(map_f(self(), nil()), store))), fstsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) , if2^#(store, m, false()) -> c_21(process^#(app(map_f(self(), nil()), sndsplit(m, store)), m), app^#(map_f(self(), nil()), sndsplit(m, store)), map_f^#(self(), nil()), sndsplit^#(m, store)) , if3^#(store, m, false()) -> c_22(process^#(sndsplit(m, app(map_f(self(), nil()), store)), m), sndsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) } Weak Trs: { fstsplit(0(), x) -> nil() , fstsplit(s(n), nil()) -> nil() , fstsplit(s(n), cons(h, t)) -> cons(h, fstsplit(n, t)) , sndsplit(0(), x) -> x , sndsplit(s(n), nil()) -> nil() , sndsplit(s(n), cons(h, t)) -> sndsplit(n, t) , empty(nil()) -> true() , empty(cons(h, t)) -> false() , leq(0(), m) -> true() , leq(s(n), 0()) -> false() , leq(s(n), s(m)) -> leq(n, m) , length(nil()) -> 0() , length(cons(h, t)) -> s(length(t)) , app(nil(), x) -> x , app(cons(h, t), x) -> cons(h, app(t, x)) , map_f(pid, nil()) -> nil() , map_f(pid, cons(h, t)) -> app(f(pid, h), map_f(pid, t)) , process(store, m) -> if1(store, m, leq(m, length(store))) , if1(store, m, true()) -> if2(store, m, empty(fstsplit(m, store))) , if1(store, m, false()) -> if3(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))) , if2(store, m, false()) -> process(app(map_f(self(), nil()), sndsplit(m, store)), m) , if3(store, m, false()) -> process(sndsplit(m, app(map_f(self(), nil()), store)), m) } Obligation: innermost runtime complexity Answer: MAYBE We estimate the number of application of {1,2,4,5,7,8,9,10,12,14,16} by applications of Pre({1,2,4,5,7,8,9,10,12,14,16}) = {3,6,11,13,15,17,18,19,20,21,22}. Here rules are labeled as follows: DPs: { 1: fstsplit^#(0(), x) -> c_1() , 2: fstsplit^#(s(n), nil()) -> c_2() , 3: fstsplit^#(s(n), cons(h, t)) -> c_3(fstsplit^#(n, t)) , 4: sndsplit^#(0(), x) -> c_4() , 5: sndsplit^#(s(n), nil()) -> c_5() , 6: sndsplit^#(s(n), cons(h, t)) -> c_6(sndsplit^#(n, t)) , 7: empty^#(nil()) -> c_7() , 8: empty^#(cons(h, t)) -> c_8() , 9: leq^#(0(), m) -> c_9() , 10: leq^#(s(n), 0()) -> c_10() , 11: leq^#(s(n), s(m)) -> c_11(leq^#(n, m)) , 12: length^#(nil()) -> c_12() , 13: length^#(cons(h, t)) -> c_13(length^#(t)) , 14: app^#(nil(), x) -> c_14() , 15: app^#(cons(h, t), x) -> c_15(app^#(t, x)) , 16: map_f^#(pid, nil()) -> c_16() , 17: map_f^#(pid, cons(h, t)) -> c_17(app^#(f(pid, h), map_f(pid, t)), map_f^#(pid, t)) , 18: process^#(store, m) -> c_18(if1^#(store, m, leq(m, length(store))), leq^#(m, length(store)), length^#(store)) , 19: if1^#(store, m, true()) -> c_19(if2^#(store, m, empty(fstsplit(m, store))), empty^#(fstsplit(m, store)), fstsplit^#(m, store)) , 20: if1^#(store, m, false()) -> c_20(if3^#(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))), empty^#(fstsplit(m, app(map_f(self(), nil()), store))), fstsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) , 21: if2^#(store, m, false()) -> c_21(process^#(app(map_f(self(), nil()), sndsplit(m, store)), m), app^#(map_f(self(), nil()), sndsplit(m, store)), map_f^#(self(), nil()), sndsplit^#(m, store)) , 22: if3^#(store, m, false()) -> c_22(process^#(sndsplit(m, app(map_f(self(), nil()), store)), m), sndsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) } We are left with following problem, upon which TcT provides the certificate MAYBE. Strict DPs: { fstsplit^#(s(n), cons(h, t)) -> c_3(fstsplit^#(n, t)) , sndsplit^#(s(n), cons(h, t)) -> c_6(sndsplit^#(n, t)) , leq^#(s(n), s(m)) -> c_11(leq^#(n, m)) , length^#(cons(h, t)) -> c_13(length^#(t)) , app^#(cons(h, t), x) -> c_15(app^#(t, x)) , map_f^#(pid, cons(h, t)) -> c_17(app^#(f(pid, h), map_f(pid, t)), map_f^#(pid, t)) , process^#(store, m) -> c_18(if1^#(store, m, leq(m, length(store))), leq^#(m, length(store)), length^#(store)) , if1^#(store, m, true()) -> c_19(if2^#(store, m, empty(fstsplit(m, store))), empty^#(fstsplit(m, store)), fstsplit^#(m, store)) , if1^#(store, m, false()) -> c_20(if3^#(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))), empty^#(fstsplit(m, app(map_f(self(), nil()), store))), fstsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) , if2^#(store, m, false()) -> c_21(process^#(app(map_f(self(), nil()), sndsplit(m, store)), m), app^#(map_f(self(), nil()), sndsplit(m, store)), map_f^#(self(), nil()), sndsplit^#(m, store)) , if3^#(store, m, false()) -> c_22(process^#(sndsplit(m, app(map_f(self(), nil()), store)), m), sndsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) } Weak DPs: { fstsplit^#(0(), x) -> c_1() , fstsplit^#(s(n), nil()) -> c_2() , sndsplit^#(0(), x) -> c_4() , sndsplit^#(s(n), nil()) -> c_5() , empty^#(nil()) -> c_7() , empty^#(cons(h, t)) -> c_8() , leq^#(0(), m) -> c_9() , leq^#(s(n), 0()) -> c_10() , length^#(nil()) -> c_12() , app^#(nil(), x) -> c_14() , map_f^#(pid, nil()) -> c_16() } Weak Trs: { fstsplit(0(), x) -> nil() , fstsplit(s(n), nil()) -> nil() , fstsplit(s(n), cons(h, t)) -> cons(h, fstsplit(n, t)) , sndsplit(0(), x) -> x , sndsplit(s(n), nil()) -> nil() , sndsplit(s(n), cons(h, t)) -> sndsplit(n, t) , empty(nil()) -> true() , empty(cons(h, t)) -> false() , leq(0(), m) -> true() , leq(s(n), 0()) -> false() , leq(s(n), s(m)) -> leq(n, m) , length(nil()) -> 0() , length(cons(h, t)) -> s(length(t)) , app(nil(), x) -> x , app(cons(h, t), x) -> cons(h, app(t, x)) , map_f(pid, nil()) -> nil() , map_f(pid, cons(h, t)) -> app(f(pid, h), map_f(pid, t)) , process(store, m) -> if1(store, m, leq(m, length(store))) , if1(store, m, true()) -> if2(store, m, empty(fstsplit(m, store))) , if1(store, m, false()) -> if3(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))) , if2(store, m, false()) -> process(app(map_f(self(), nil()), sndsplit(m, store)), m) , if3(store, m, false()) -> process(sndsplit(m, app(map_f(self(), nil()), store)), m) } Obligation: innermost runtime complexity Answer: MAYBE The following weak DPs constitute a sub-graph of the DG that is closed under successors. The DPs are removed. { fstsplit^#(0(), x) -> c_1() , fstsplit^#(s(n), nil()) -> c_2() , sndsplit^#(0(), x) -> c_4() , sndsplit^#(s(n), nil()) -> c_5() , empty^#(nil()) -> c_7() , empty^#(cons(h, t)) -> c_8() , leq^#(0(), m) -> c_9() , leq^#(s(n), 0()) -> c_10() , length^#(nil()) -> c_12() , app^#(nil(), x) -> c_14() , map_f^#(pid, nil()) -> c_16() } We are left with following problem, upon which TcT provides the certificate MAYBE. Strict DPs: { fstsplit^#(s(n), cons(h, t)) -> c_3(fstsplit^#(n, t)) , sndsplit^#(s(n), cons(h, t)) -> c_6(sndsplit^#(n, t)) , leq^#(s(n), s(m)) -> c_11(leq^#(n, m)) , length^#(cons(h, t)) -> c_13(length^#(t)) , app^#(cons(h, t), x) -> c_15(app^#(t, x)) , map_f^#(pid, cons(h, t)) -> c_17(app^#(f(pid, h), map_f(pid, t)), map_f^#(pid, t)) , process^#(store, m) -> c_18(if1^#(store, m, leq(m, length(store))), leq^#(m, length(store)), length^#(store)) , if1^#(store, m, true()) -> c_19(if2^#(store, m, empty(fstsplit(m, store))), empty^#(fstsplit(m, store)), fstsplit^#(m, store)) , if1^#(store, m, false()) -> c_20(if3^#(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))), empty^#(fstsplit(m, app(map_f(self(), nil()), store))), fstsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) , if2^#(store, m, false()) -> c_21(process^#(app(map_f(self(), nil()), sndsplit(m, store)), m), app^#(map_f(self(), nil()), sndsplit(m, store)), map_f^#(self(), nil()), sndsplit^#(m, store)) , if3^#(store, m, false()) -> c_22(process^#(sndsplit(m, app(map_f(self(), nil()), store)), m), sndsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) } Weak Trs: { fstsplit(0(), x) -> nil() , fstsplit(s(n), nil()) -> nil() , fstsplit(s(n), cons(h, t)) -> cons(h, fstsplit(n, t)) , sndsplit(0(), x) -> x , sndsplit(s(n), nil()) -> nil() , sndsplit(s(n), cons(h, t)) -> sndsplit(n, t) , empty(nil()) -> true() , empty(cons(h, t)) -> false() , leq(0(), m) -> true() , leq(s(n), 0()) -> false() , leq(s(n), s(m)) -> leq(n, m) , length(nil()) -> 0() , length(cons(h, t)) -> s(length(t)) , app(nil(), x) -> x , app(cons(h, t), x) -> cons(h, app(t, x)) , map_f(pid, nil()) -> nil() , map_f(pid, cons(h, t)) -> app(f(pid, h), map_f(pid, t)) , process(store, m) -> if1(store, m, leq(m, length(store))) , if1(store, m, true()) -> if2(store, m, empty(fstsplit(m, store))) , if1(store, m, false()) -> if3(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))) , if2(store, m, false()) -> process(app(map_f(self(), nil()), sndsplit(m, store)), m) , if3(store, m, false()) -> process(sndsplit(m, app(map_f(self(), nil()), store)), m) } Obligation: innermost runtime complexity Answer: MAYBE Due to missing edges in the dependency-graph, the right-hand sides of following rules could be simplified: { map_f^#(pid, cons(h, t)) -> c_17(app^#(f(pid, h), map_f(pid, t)), map_f^#(pid, t)) , if1^#(store, m, true()) -> c_19(if2^#(store, m, empty(fstsplit(m, store))), empty^#(fstsplit(m, store)), fstsplit^#(m, store)) , if1^#(store, m, false()) -> c_20(if3^#(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))), empty^#(fstsplit(m, app(map_f(self(), nil()), store))), fstsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) , if2^#(store, m, false()) -> c_21(process^#(app(map_f(self(), nil()), sndsplit(m, store)), m), app^#(map_f(self(), nil()), sndsplit(m, store)), map_f^#(self(), nil()), sndsplit^#(m, store)) , if3^#(store, m, false()) -> c_22(process^#(sndsplit(m, app(map_f(self(), nil()), store)), m), sndsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store), map_f^#(self(), nil())) } We are left with following problem, upon which TcT provides the certificate MAYBE. Strict DPs: { fstsplit^#(s(n), cons(h, t)) -> c_1(fstsplit^#(n, t)) , sndsplit^#(s(n), cons(h, t)) -> c_2(sndsplit^#(n, t)) , leq^#(s(n), s(m)) -> c_3(leq^#(n, m)) , length^#(cons(h, t)) -> c_4(length^#(t)) , app^#(cons(h, t), x) -> c_5(app^#(t, x)) , map_f^#(pid, cons(h, t)) -> c_6(map_f^#(pid, t)) , process^#(store, m) -> c_7(if1^#(store, m, leq(m, length(store))), leq^#(m, length(store)), length^#(store)) , if1^#(store, m, true()) -> c_8(if2^#(store, m, empty(fstsplit(m, store))), fstsplit^#(m, store)) , if1^#(store, m, false()) -> c_9(if3^#(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))), fstsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store)) , if2^#(store, m, false()) -> c_10(process^#(app(map_f(self(), nil()), sndsplit(m, store)), m), app^#(map_f(self(), nil()), sndsplit(m, store)), sndsplit^#(m, store)) , if3^#(store, m, false()) -> c_11(process^#(sndsplit(m, app(map_f(self(), nil()), store)), m), sndsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store)) } Weak Trs: { fstsplit(0(), x) -> nil() , fstsplit(s(n), nil()) -> nil() , fstsplit(s(n), cons(h, t)) -> cons(h, fstsplit(n, t)) , sndsplit(0(), x) -> x , sndsplit(s(n), nil()) -> nil() , sndsplit(s(n), cons(h, t)) -> sndsplit(n, t) , empty(nil()) -> true() , empty(cons(h, t)) -> false() , leq(0(), m) -> true() , leq(s(n), 0()) -> false() , leq(s(n), s(m)) -> leq(n, m) , length(nil()) -> 0() , length(cons(h, t)) -> s(length(t)) , app(nil(), x) -> x , app(cons(h, t), x) -> cons(h, app(t, x)) , map_f(pid, nil()) -> nil() , map_f(pid, cons(h, t)) -> app(f(pid, h), map_f(pid, t)) , process(store, m) -> if1(store, m, leq(m, length(store))) , if1(store, m, true()) -> if2(store, m, empty(fstsplit(m, store))) , if1(store, m, false()) -> if3(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))) , if2(store, m, false()) -> process(app(map_f(self(), nil()), sndsplit(m, store)), m) , if3(store, m, false()) -> process(sndsplit(m, app(map_f(self(), nil()), store)), m) } Obligation: innermost runtime complexity Answer: MAYBE We replace rewrite rules by usable rules: Weak Usable Rules: { fstsplit(0(), x) -> nil() , fstsplit(s(n), nil()) -> nil() , fstsplit(s(n), cons(h, t)) -> cons(h, fstsplit(n, t)) , sndsplit(0(), x) -> x , sndsplit(s(n), nil()) -> nil() , sndsplit(s(n), cons(h, t)) -> sndsplit(n, t) , empty(nil()) -> true() , empty(cons(h, t)) -> false() , leq(0(), m) -> true() , leq(s(n), 0()) -> false() , leq(s(n), s(m)) -> leq(n, m) , length(nil()) -> 0() , length(cons(h, t)) -> s(length(t)) , app(nil(), x) -> x , app(cons(h, t), x) -> cons(h, app(t, x)) , map_f(pid, nil()) -> nil() , map_f(pid, cons(h, t)) -> app(f(pid, h), map_f(pid, t)) } We are left with following problem, upon which TcT provides the certificate MAYBE. Strict DPs: { fstsplit^#(s(n), cons(h, t)) -> c_1(fstsplit^#(n, t)) , sndsplit^#(s(n), cons(h, t)) -> c_2(sndsplit^#(n, t)) , leq^#(s(n), s(m)) -> c_3(leq^#(n, m)) , length^#(cons(h, t)) -> c_4(length^#(t)) , app^#(cons(h, t), x) -> c_5(app^#(t, x)) , map_f^#(pid, cons(h, t)) -> c_6(map_f^#(pid, t)) , process^#(store, m) -> c_7(if1^#(store, m, leq(m, length(store))), leq^#(m, length(store)), length^#(store)) , if1^#(store, m, true()) -> c_8(if2^#(store, m, empty(fstsplit(m, store))), fstsplit^#(m, store)) , if1^#(store, m, false()) -> c_9(if3^#(store, m, empty(fstsplit(m, app(map_f(self(), nil()), store)))), fstsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store)) , if2^#(store, m, false()) -> c_10(process^#(app(map_f(self(), nil()), sndsplit(m, store)), m), app^#(map_f(self(), nil()), sndsplit(m, store)), sndsplit^#(m, store)) , if3^#(store, m, false()) -> c_11(process^#(sndsplit(m, app(map_f(self(), nil()), store)), m), sndsplit^#(m, app(map_f(self(), nil()), store)), app^#(map_f(self(), nil()), store)) } Weak Trs: { fstsplit(0(), x) -> nil() , fstsplit(s(n), nil()) -> nil() , fstsplit(s(n), cons(h, t)) -> cons(h, fstsplit(n, t)) , sndsplit(0(), x) -> x , sndsplit(s(n), nil()) -> nil() , sndsplit(s(n), cons(h, t)) -> sndsplit(n, t) , empty(nil()) -> true() , empty(cons(h, t)) -> false() , leq(0(), m) -> true() , leq(s(n), 0()) -> false() , leq(s(n), s(m)) -> leq(n, m) , length(nil()) -> 0() , length(cons(h, t)) -> s(length(t)) , app(nil(), x) -> x , app(cons(h, t), x) -> cons(h, app(t, x)) , map_f(pid, nil()) -> nil() , map_f(pid, cons(h, t)) -> app(f(pid, h), map_f(pid, t)) } Obligation: innermost runtime complexity Answer: MAYBE The input cannot be shown compatible Arrrr..