(VAR V2 L N V1 V X1 X2 X) (RULES zeros -> cons(0,n__zeros) U11(tt) -> tt U21(tt) -> tt U31(tt) -> tt U41(tt,V2) -> U42(isNatIList(activate(V2))) U42(tt) -> tt U51(tt,V2) -> U52(isNatList(activate(V2))) U52(tt) -> tt U61(tt,L,N) -> U62(isNat(activate(N)),activate(L)) U62(tt,L) -> s(length(activate(L))) isNat(n__0) -> tt isNat(n__length(V1)) -> U11(isNatList(activate(V1))) isNat(n__s(V1)) -> U21(isNat(activate(V1))) isNatIList(V) -> U31(isNatList(activate(V))) isNatIList(n__zeros) -> tt isNatIList(n__cons(V1,V2)) -> U41(isNat(activate(V1)),activate(V2)) isNatList(n__nil) -> tt isNatList(n__cons(V1,V2)) -> U51(isNat(activate(V1)),activate(V2)) length(nil) -> 0 length(cons(N,L)) -> U61(isNatList(activate(L)),activate(L),N) zeros -> n__zeros 0 -> n__0 length(X) -> n__length(X) s(X) -> n__s(X) cons(X1,X2) -> n__cons(X1,X2) nil -> n__nil activate(n__zeros) -> zeros activate(n__0) -> 0 activate(n__length(X)) -> length(X) activate(n__s(X)) -> s(X) activate(n__cons(X1,X2)) -> cons(X1,X2) activate(n__nil) -> nil activate(X) -> X )