(VAR X XS N Y YS X1 X2)
(RULES 
active(pairNs) -> mark(cons(0,incr(oddNs)))
active(oddNs) -> mark(incr(pairNs))
active(incr(cons(X,XS))) -> mark(cons(s(X),incr(XS)))
active(take(0,XS)) -> mark(nil)
active(take(s(N),cons(X,XS))) -> mark(cons(X,take(N,XS)))
active(zip(nil,XS)) -> mark(nil)
active(zip(X,nil)) -> mark(nil)
active(zip(cons(X,XS),cons(Y,YS))) -> mark(cons(pair(X,Y),zip(XS,YS)))
active(tail(cons(X,XS))) -> mark(XS)
active(repItems(nil)) -> mark(nil)
active(repItems(cons(X,XS))) -> mark(cons(X,cons(X,repItems(XS))))
active(cons(X1,X2)) -> cons(active(X1),X2)
active(incr(X)) -> incr(active(X))
active(s(X)) -> s(active(X))
active(take(X1,X2)) -> take(active(X1),X2)
active(take(X1,X2)) -> take(X1,active(X2))
active(zip(X1,X2)) -> zip(active(X1),X2)
active(zip(X1,X2)) -> zip(X1,active(X2))
active(pair(X1,X2)) -> pair(active(X1),X2)
active(pair(X1,X2)) -> pair(X1,active(X2))
active(tail(X)) -> tail(active(X))
active(repItems(X)) -> repItems(active(X))
cons(mark(X1),X2) -> mark(cons(X1,X2))
incr(mark(X)) -> mark(incr(X))
s(mark(X)) -> mark(s(X))
take(mark(X1),X2) -> mark(take(X1,X2))
take(X1,mark(X2)) -> mark(take(X1,X2))
zip(mark(X1),X2) -> mark(zip(X1,X2))
zip(X1,mark(X2)) -> mark(zip(X1,X2))
pair(mark(X1),X2) -> mark(pair(X1,X2))
pair(X1,mark(X2)) -> mark(pair(X1,X2))
tail(mark(X)) -> mark(tail(X))
repItems(mark(X)) -> mark(repItems(X))
proper(pairNs) -> ok(pairNs)
proper(cons(X1,X2)) -> cons(proper(X1),proper(X2))
proper(0) -> ok(0)
proper(incr(X)) -> incr(proper(X))
proper(oddNs) -> ok(oddNs)
proper(s(X)) -> s(proper(X))
proper(take(X1,X2)) -> take(proper(X1),proper(X2))
proper(nil) -> ok(nil)
proper(zip(X1,X2)) -> zip(proper(X1),proper(X2))
proper(pair(X1,X2)) -> pair(proper(X1),proper(X2))
proper(tail(X)) -> tail(proper(X))
proper(repItems(X)) -> repItems(proper(X))
cons(ok(X1),ok(X2)) -> ok(cons(X1,X2))
incr(ok(X)) -> ok(incr(X))
s(ok(X)) -> ok(s(X))
take(ok(X1),ok(X2)) -> ok(take(X1,X2))
zip(ok(X1),ok(X2)) -> ok(zip(X1,X2))
pair(ok(X1),ok(X2)) -> ok(pair(X1,X2))
tail(ok(X)) -> ok(tail(X))
repItems(ok(X)) -> ok(repItems(X))
top(mark(X)) -> top(proper(X))
top(ok(X)) -> top(active(X))
)