(VAR L N V V1 V2 X X1 X2 X3 )
(RULES 
        active(zeros) -> mark(cons(0, zeros))
        active(U11(tt, V1)) -> mark(U12(isNatIListKind(V1), V1))
        active(U12(tt, V1)) -> mark(U13(isNatList(V1)))
        active(U13(tt)) -> mark(tt)
        active(U21(tt, V1)) -> mark(U22(isNatKind(V1), V1))
        active(U22(tt, V1)) -> mark(U23(isNat(V1)))
        active(U23(tt)) -> mark(tt)
        active(U31(tt, V)) -> mark(U32(isNatIListKind(V), V))
        active(U32(tt, V)) -> mark(U33(isNatList(V)))
        active(U33(tt)) -> mark(tt)
        active(U41(tt, V1, V2)) -> mark(U42(isNatKind(V1), V1, V2))
        active(U42(tt, V1, V2)) -> mark(U43(isNatIListKind(V2), V1, V2))
        active(U43(tt, V1, V2)) -> mark(U44(isNatIListKind(V2), V1, V2))
        active(U44(tt, V1, V2)) -> mark(U45(isNat(V1), V2))
        active(U45(tt, V2)) -> mark(U46(isNatIList(V2)))
        active(U46(tt)) -> mark(tt)
        active(U51(tt, V2)) -> mark(U52(isNatIListKind(V2)))
        active(U52(tt)) -> mark(tt)
        active(U61(tt)) -> mark(tt)
        active(U71(tt)) -> mark(tt)
        active(U81(tt, V1, V2)) -> mark(U82(isNatKind(V1), V1, V2))
        active(U82(tt, V1, V2)) -> mark(U83(isNatIListKind(V2), V1, V2))
        active(U83(tt, V1, V2)) -> mark(U84(isNatIListKind(V2), V1, V2))
        active(U84(tt, V1, V2)) -> mark(U85(isNat(V1), V2))
        active(U85(tt, V2)) -> mark(U86(isNatList(V2)))
        active(U86(tt)) -> mark(tt)
        active(U91(tt, L, N)) -> mark(U92(isNatIListKind(L), L, N))
        active(U92(tt, L, N)) -> mark(U93(isNat(N), L, N))
        active(U93(tt, L, N)) -> mark(U94(isNatKind(N), L))
        active(U94(tt, L)) -> mark(s(length(L)))
        active(isNat(0)) -> mark(tt)
        active(isNat(length(V1))) -> mark(U11(isNatIListKind(V1), V1))
        active(isNat(s(V1))) -> mark(U21(isNatKind(V1), V1))
        active(isNatIList(V)) -> mark(U31(isNatIListKind(V), V))
        active(isNatIList(zeros)) -> mark(tt)
        active(isNatIList(cons(V1, V2))) -> mark(U41(isNatKind(V1), V1, V2))
        active(isNatIListKind(nil)) -> mark(tt)
        active(isNatIListKind(zeros)) -> mark(tt)
        active(isNatIListKind(cons(V1, V2))) -> mark(U51(isNatKind(V1), V2))
        active(isNatKind(0)) -> mark(tt)
        active(isNatKind(length(V1))) -> mark(U61(isNatIListKind(V1)))
        active(isNatKind(s(V1))) -> mark(U71(isNatKind(V1)))
        active(isNatList(nil)) -> mark(tt)
        active(isNatList(cons(V1, V2))) -> mark(U81(isNatKind(V1), V1, V2))
        active(length(nil)) -> mark(0)
        active(length(cons(N, L))) -> mark(U91(isNatList(L), L, 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(isNatIListKind(X)) -> active(isNatIListKind(X))
        mark(U13(X)) -> active(U13(mark(X)))
        mark(isNatList(X)) -> active(isNatList(X))
        mark(U21(X1, X2)) -> active(U21(mark(X1), X2))
        mark(U22(X1, X2)) -> active(U22(mark(X1), X2))
        mark(isNatKind(X)) -> active(isNatKind(X))
        mark(U23(X)) -> active(U23(mark(X)))
        mark(isNat(X)) -> active(isNat(X))
        mark(U31(X1, X2)) -> active(U31(mark(X1), X2))
        mark(U32(X1, X2)) -> active(U32(mark(X1), X2))
        mark(U33(X)) -> active(U33(mark(X)))
        mark(U41(X1, X2, X3)) -> active(U41(mark(X1), X2, X3))
        mark(U42(X1, X2, X3)) -> active(U42(mark(X1), X2, X3))
        mark(U43(X1, X2, X3)) -> active(U43(mark(X1), X2, X3))
        mark(U44(X1, X2, X3)) -> active(U44(mark(X1), X2, X3))
        mark(U45(X1, X2)) -> active(U45(mark(X1), X2))
        mark(U46(X)) -> active(U46(mark(X)))
        mark(isNatIList(X)) -> active(isNatIList(X))
        mark(U51(X1, X2)) -> active(U51(mark(X1), X2))
        mark(U52(X)) -> active(U52(mark(X)))
        mark(U61(X)) -> active(U61(mark(X)))
        mark(U71(X)) -> active(U71(mark(X)))
        mark(U81(X1, X2, X3)) -> active(U81(mark(X1), X2, X3))
        mark(U82(X1, X2, X3)) -> active(U82(mark(X1), X2, X3))
        mark(U83(X1, X2, X3)) -> active(U83(mark(X1), X2, X3))
        mark(U84(X1, X2, X3)) -> active(U84(mark(X1), X2, X3))
        mark(U85(X1, X2)) -> active(U85(mark(X1), X2))
        mark(U86(X)) -> active(U86(mark(X)))
        mark(U91(X1, X2, X3)) -> active(U91(mark(X1), X2, X3))
        mark(U92(X1, X2, X3)) -> active(U92(mark(X1), X2, X3))
        mark(U93(X1, X2, X3)) -> active(U93(mark(X1), X2, X3))
        mark(U94(X1, X2)) -> active(U94(mark(X1), X2))
        mark(s(X)) -> active(s(mark(X)))
        mark(length(X)) -> active(length(mark(X)))
        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)
        isNatIListKind(mark(X)) -> isNatIListKind(X)
        isNatIListKind(active(X)) -> isNatIListKind(X)
        U13(mark(X)) -> U13(X)
        U13(active(X)) -> U13(X)
        isNatList(mark(X)) -> isNatList(X)
        isNatList(active(X)) -> isNatList(X)
        U21(mark(X1), X2) -> U21(X1, X2)
        U21(X1, mark(X2)) -> U21(X1, X2)
        U21(active(X1), X2) -> U21(X1, X2)
        U21(X1, active(X2)) -> U21(X1, X2)
        U22(mark(X1), X2) -> U22(X1, X2)
        U22(X1, mark(X2)) -> U22(X1, X2)
        U22(active(X1), X2) -> U22(X1, X2)
        U22(X1, active(X2)) -> U22(X1, X2)
        isNatKind(mark(X)) -> isNatKind(X)
        isNatKind(active(X)) -> isNatKind(X)
        U23(mark(X)) -> U23(X)
        U23(active(X)) -> U23(X)
        isNat(mark(X)) -> isNat(X)
        isNat(active(X)) -> isNat(X)
        U31(mark(X1), X2) -> U31(X1, X2)
        U31(X1, mark(X2)) -> U31(X1, X2)
        U31(active(X1), X2) -> U31(X1, X2)
        U31(X1, active(X2)) -> U31(X1, X2)
        U32(mark(X1), X2) -> U32(X1, X2)
        U32(X1, mark(X2)) -> U32(X1, X2)
        U32(active(X1), X2) -> U32(X1, X2)
        U32(X1, active(X2)) -> U32(X1, X2)
        U33(mark(X)) -> U33(X)
        U33(active(X)) -> U33(X)
        U41(mark(X1), X2, X3) -> U41(X1, X2, X3)
        U41(X1, mark(X2), X3) -> U41(X1, X2, X3)
        U41(X1, X2, mark(X3)) -> U41(X1, X2, X3)
        U41(active(X1), X2, X3) -> U41(X1, X2, X3)
        U41(X1, active(X2), X3) -> U41(X1, X2, X3)
        U41(X1, X2, active(X3)) -> U41(X1, X2, X3)
        U42(mark(X1), X2, X3) -> U42(X1, X2, X3)
        U42(X1, mark(X2), X3) -> U42(X1, X2, X3)
        U42(X1, X2, mark(X3)) -> U42(X1, X2, X3)
        U42(active(X1), X2, X3) -> U42(X1, X2, X3)
        U42(X1, active(X2), X3) -> U42(X1, X2, X3)
        U42(X1, X2, active(X3)) -> U42(X1, X2, X3)
        U43(mark(X1), X2, X3) -> U43(X1, X2, X3)
        U43(X1, mark(X2), X3) -> U43(X1, X2, X3)
        U43(X1, X2, mark(X3)) -> U43(X1, X2, X3)
        U43(active(X1), X2, X3) -> U43(X1, X2, X3)
        U43(X1, active(X2), X3) -> U43(X1, X2, X3)
        U43(X1, X2, active(X3)) -> U43(X1, X2, X3)
        U44(mark(X1), X2, X3) -> U44(X1, X2, X3)
        U44(X1, mark(X2), X3) -> U44(X1, X2, X3)
        U44(X1, X2, mark(X3)) -> U44(X1, X2, X3)
        U44(active(X1), X2, X3) -> U44(X1, X2, X3)
        U44(X1, active(X2), X3) -> U44(X1, X2, X3)
        U44(X1, X2, active(X3)) -> U44(X1, X2, X3)
        U45(mark(X1), X2) -> U45(X1, X2)
        U45(X1, mark(X2)) -> U45(X1, X2)
        U45(active(X1), X2) -> U45(X1, X2)
        U45(X1, active(X2)) -> U45(X1, X2)
        U46(mark(X)) -> U46(X)
        U46(active(X)) -> U46(X)
        isNatIList(mark(X)) -> isNatIList(X)
        isNatIList(active(X)) -> isNatIList(X)
        U51(mark(X1), X2) -> U51(X1, X2)
        U51(X1, mark(X2)) -> U51(X1, X2)
        U51(active(X1), X2) -> U51(X1, X2)
        U51(X1, active(X2)) -> U51(X1, X2)
        U52(mark(X)) -> U52(X)
        U52(active(X)) -> U52(X)
        U61(mark(X)) -> U61(X)
        U61(active(X)) -> U61(X)
        U71(mark(X)) -> U71(X)
        U71(active(X)) -> U71(X)
        U81(mark(X1), X2, X3) -> U81(X1, X2, X3)
        U81(X1, mark(X2), X3) -> U81(X1, X2, X3)
        U81(X1, X2, mark(X3)) -> U81(X1, X2, X3)
        U81(active(X1), X2, X3) -> U81(X1, X2, X3)
        U81(X1, active(X2), X3) -> U81(X1, X2, X3)
        U81(X1, X2, active(X3)) -> U81(X1, X2, X3)
        U82(mark(X1), X2, X3) -> U82(X1, X2, X3)
        U82(X1, mark(X2), X3) -> U82(X1, X2, X3)
        U82(X1, X2, mark(X3)) -> U82(X1, X2, X3)
        U82(active(X1), X2, X3) -> U82(X1, X2, X3)
        U82(X1, active(X2), X3) -> U82(X1, X2, X3)
        U82(X1, X2, active(X3)) -> U82(X1, X2, X3)
        U83(mark(X1), X2, X3) -> U83(X1, X2, X3)
        U83(X1, mark(X2), X3) -> U83(X1, X2, X3)
        U83(X1, X2, mark(X3)) -> U83(X1, X2, X3)
        U83(active(X1), X2, X3) -> U83(X1, X2, X3)
        U83(X1, active(X2), X3) -> U83(X1, X2, X3)
        U83(X1, X2, active(X3)) -> U83(X1, X2, X3)
        U84(mark(X1), X2, X3) -> U84(X1, X2, X3)
        U84(X1, mark(X2), X3) -> U84(X1, X2, X3)
        U84(X1, X2, mark(X3)) -> U84(X1, X2, X3)
        U84(active(X1), X2, X3) -> U84(X1, X2, X3)
        U84(X1, active(X2), X3) -> U84(X1, X2, X3)
        U84(X1, X2, active(X3)) -> U84(X1, X2, X3)
        U85(mark(X1), X2) -> U85(X1, X2)
        U85(X1, mark(X2)) -> U85(X1, X2)
        U85(active(X1), X2) -> U85(X1, X2)
        U85(X1, active(X2)) -> U85(X1, X2)
        U86(mark(X)) -> U86(X)
        U86(active(X)) -> U86(X)
        U91(mark(X1), X2, X3) -> U91(X1, X2, X3)
        U91(X1, mark(X2), X3) -> U91(X1, X2, X3)
        U91(X1, X2, mark(X3)) -> U91(X1, X2, X3)
        U91(active(X1), X2, X3) -> U91(X1, X2, X3)
        U91(X1, active(X2), X3) -> U91(X1, X2, X3)
        U91(X1, X2, active(X3)) -> U91(X1, X2, X3)
        U92(mark(X1), X2, X3) -> U92(X1, X2, X3)
        U92(X1, mark(X2), X3) -> U92(X1, X2, X3)
        U92(X1, X2, mark(X3)) -> U92(X1, X2, X3)
        U92(active(X1), X2, X3) -> U92(X1, X2, X3)
        U92(X1, active(X2), X3) -> U92(X1, X2, X3)
        U92(X1, X2, active(X3)) -> U92(X1, X2, X3)
        U93(mark(X1), X2, X3) -> U93(X1, X2, X3)
        U93(X1, mark(X2), X3) -> U93(X1, X2, X3)
        U93(X1, X2, mark(X3)) -> U93(X1, X2, X3)
        U93(active(X1), X2, X3) -> U93(X1, X2, X3)
        U93(X1, active(X2), X3) -> U93(X1, X2, X3)
        U93(X1, X2, active(X3)) -> U93(X1, X2, X3)
        U94(mark(X1), X2) -> U94(X1, X2)
        U94(X1, mark(X2)) -> U94(X1, X2)
        U94(active(X1), X2) -> U94(X1, X2)
        U94(X1, active(X2)) -> U94(X1, X2)
        s(mark(X)) -> s(X)
        s(active(X)) -> s(X)
        length(mark(X)) -> length(X)
        length(active(X)) -> length(X)
        
)