(VAR IL L M N X X1 X2 X3 X4 )
(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)
        
)