(VAR L IL M N X1 X2 X3 X4 X)
(RULES 
active(zeros) -> mark(cons(0,zeros))
active(U11(tt,L)) -> mark(U12(tt,L))
active(U12(tt,L)) -> mark(s(length(L)))
active(U21(tt,IL,M,N)) -> mark(U22(tt,IL,M,N))
active(U22(tt,IL,M,N)) -> mark(U23(tt,IL,M,N))
active(U23(tt,IL,M,N)) -> mark(cons(N,take(M,IL)))
active(length(nil)) -> mark(0)
active(length(cons(N,L))) -> mark(U11(tt,L))
active(take(0,IL)) -> mark(nil)
active(take(s(M),cons(N,IL))) -> mark(U21(tt,IL,M,N))
mark(zeros) -> active(zeros)
mark(cons(X1,X2)) -> active(cons(mark(X1),X2))
mark(0) -> active(0)
mark(U11(X1,X2)) -> active(U11(mark(X1),X2))
mark(tt) -> active(tt)
mark(U12(X1,X2)) -> active(U12(mark(X1),X2))
mark(s(X)) -> active(s(mark(X)))
mark(length(X)) -> active(length(mark(X)))
mark(U21(X1,X2,X3,X4)) -> active(U21(mark(X1),X2,X3,X4))
mark(U22(X1,X2,X3,X4)) -> active(U22(mark(X1),X2,X3,X4))
mark(U23(X1,X2,X3,X4)) -> active(U23(mark(X1),X2,X3,X4))
mark(take(X1,X2)) -> active(take(mark(X1),mark(X2)))
mark(nil) -> active(nil)
cons(mark(X1),X2) -> cons(X1,X2)
cons(X1,mark(X2)) -> cons(X1,X2)
cons(active(X1),X2) -> cons(X1,X2)
cons(X1,active(X2)) -> cons(X1,X2)
U11(mark(X1),X2) -> U11(X1,X2)
U11(X1,mark(X2)) -> U11(X1,X2)
U11(active(X1),X2) -> U11(X1,X2)
U11(X1,active(X2)) -> U11(X1,X2)
U12(mark(X1),X2) -> U12(X1,X2)
U12(X1,mark(X2)) -> U12(X1,X2)
U12(active(X1),X2) -> U12(X1,X2)
U12(X1,active(X2)) -> U12(X1,X2)
s(mark(X)) -> s(X)
s(active(X)) -> s(X)
length(mark(X)) -> length(X)
length(active(X)) -> length(X)
U21(mark(X1),X2,X3,X4) -> U21(X1,X2,X3,X4)
U21(X1,mark(X2),X3,X4) -> U21(X1,X2,X3,X4)
U21(X1,X2,mark(X3),X4) -> U21(X1,X2,X3,X4)
U21(X1,X2,X3,mark(X4)) -> U21(X1,X2,X3,X4)
U21(active(X1),X2,X3,X4) -> U21(X1,X2,X3,X4)
U21(X1,active(X2),X3,X4) -> U21(X1,X2,X3,X4)
U21(X1,X2,active(X3),X4) -> U21(X1,X2,X3,X4)
U21(X1,X2,X3,active(X4)) -> U21(X1,X2,X3,X4)
U22(mark(X1),X2,X3,X4) -> U22(X1,X2,X3,X4)
U22(X1,mark(X2),X3,X4) -> U22(X1,X2,X3,X4)
U22(X1,X2,mark(X3),X4) -> U22(X1,X2,X3,X4)
U22(X1,X2,X3,mark(X4)) -> U22(X1,X2,X3,X4)
U22(active(X1),X2,X3,X4) -> U22(X1,X2,X3,X4)
U22(X1,active(X2),X3,X4) -> U22(X1,X2,X3,X4)
U22(X1,X2,active(X3),X4) -> U22(X1,X2,X3,X4)
U22(X1,X2,X3,active(X4)) -> U22(X1,X2,X3,X4)
U23(mark(X1),X2,X3,X4) -> U23(X1,X2,X3,X4)
U23(X1,mark(X2),X3,X4) -> U23(X1,X2,X3,X4)
U23(X1,X2,mark(X3),X4) -> U23(X1,X2,X3,X4)
U23(X1,X2,X3,mark(X4)) -> U23(X1,X2,X3,X4)
U23(active(X1),X2,X3,X4) -> U23(X1,X2,X3,X4)
U23(X1,active(X2),X3,X4) -> U23(X1,X2,X3,X4)
U23(X1,X2,active(X3),X4) -> U23(X1,X2,X3,X4)
U23(X1,X2,X3,active(X4)) -> U23(X1,X2,X3,X4)
take(mark(X1),X2) -> take(X1,X2)
take(X1,mark(X2)) -> take(X1,X2)
take(active(X1),X2) -> take(X1,X2)
take(X1,active(X2)) -> take(X1,X2)
)