(VAR N XS X Y YS ZS X1 X2 X3 X4)
(RULES 
a__U11(tt,N,XS) -> a__U12(tt,N,XS)
a__U12(tt,N,XS) -> a__snd(a__splitAt(mark(N),mark(XS)))
a__U21(tt,X) -> a__U22(tt,X)
a__U22(tt,X) -> mark(X)
a__U31(tt,N) -> a__U32(tt,N)
a__U32(tt,N) -> mark(N)
a__U41(tt,N,XS) -> a__U42(tt,N,XS)
a__U42(tt,N,XS) -> a__head(a__afterNth(mark(N),mark(XS)))
a__U51(tt,Y) -> a__U52(tt,Y)
a__U52(tt,Y) -> mark(Y)
a__U61(tt,N,X,XS) -> a__U62(tt,N,X,XS)
a__U62(tt,N,X,XS) -> a__U63(tt,N,X,XS)
a__U63(tt,N,X,XS) -> a__U64(a__splitAt(mark(N),mark(XS)),X)
a__U64(pair(YS,ZS),X) -> pair(cons(mark(X),YS),mark(ZS))
a__U71(tt,XS) -> a__U72(tt,XS)
a__U72(tt,XS) -> mark(XS)
a__U81(tt,N,XS) -> a__U82(tt,N,XS)
a__U82(tt,N,XS) -> a__fst(a__splitAt(mark(N),mark(XS)))
a__afterNth(N,XS) -> a__U11(tt,N,XS)
a__fst(pair(X,Y)) -> a__U21(tt,X)
a__head(cons(N,XS)) -> a__U31(tt,N)
a__natsFrom(N) -> cons(mark(N),natsFrom(s(N)))
a__sel(N,XS) -> a__U41(tt,N,XS)
a__snd(pair(X,Y)) -> a__U51(tt,Y)
a__splitAt(0,XS) -> pair(nil,mark(XS))
a__splitAt(s(N),cons(X,XS)) -> a__U61(tt,N,X,XS)
a__tail(cons(N,XS)) -> a__U71(tt,XS)
a__take(N,XS) -> a__U81(tt,N,XS)
mark(U11(X1,X2,X3)) -> a__U11(mark(X1),X2,X3)
mark(U12(X1,X2,X3)) -> a__U12(mark(X1),X2,X3)
mark(snd(X)) -> a__snd(mark(X))
mark(splitAt(X1,X2)) -> a__splitAt(mark(X1),mark(X2))
mark(U21(X1,X2)) -> a__U21(mark(X1),X2)
mark(U22(X1,X2)) -> a__U22(mark(X1),X2)
mark(U31(X1,X2)) -> a__U31(mark(X1),X2)
mark(U32(X1,X2)) -> a__U32(mark(X1),X2)
mark(U41(X1,X2,X3)) -> a__U41(mark(X1),X2,X3)
mark(U42(X1,X2,X3)) -> a__U42(mark(X1),X2,X3)
mark(head(X)) -> a__head(mark(X))
mark(afterNth(X1,X2)) -> a__afterNth(mark(X1),mark(X2))
mark(U51(X1,X2)) -> a__U51(mark(X1),X2)
mark(U52(X1,X2)) -> a__U52(mark(X1),X2)
mark(U61(X1,X2,X3,X4)) -> a__U61(mark(X1),X2,X3,X4)
mark(U62(X1,X2,X3,X4)) -> a__U62(mark(X1),X2,X3,X4)
mark(U63(X1,X2,X3,X4)) -> a__U63(mark(X1),X2,X3,X4)
mark(U64(X1,X2)) -> a__U64(mark(X1),X2)
mark(U71(X1,X2)) -> a__U71(mark(X1),X2)
mark(U72(X1,X2)) -> a__U72(mark(X1),X2)
mark(U81(X1,X2,X3)) -> a__U81(mark(X1),X2,X3)
mark(U82(X1,X2,X3)) -> a__U82(mark(X1),X2,X3)
mark(fst(X)) -> a__fst(mark(X))
mark(natsFrom(X)) -> a__natsFrom(mark(X))
mark(sel(X1,X2)) -> a__sel(mark(X1),mark(X2))
mark(tail(X)) -> a__tail(mark(X))
mark(take(X1,X2)) -> a__take(mark(X1),mark(X2))
mark(tt) -> tt
mark(pair(X1,X2)) -> pair(mark(X1),mark(X2))
mark(cons(X1,X2)) -> cons(mark(X1),X2)
mark(s(X)) -> s(mark(X))
mark(0) -> 0
mark(nil) -> nil
a__U11(X1,X2,X3) -> U11(X1,X2,X3)
a__U12(X1,X2,X3) -> U12(X1,X2,X3)
a__snd(X) -> snd(X)
a__splitAt(X1,X2) -> splitAt(X1,X2)
a__U21(X1,X2) -> U21(X1,X2)
a__U22(X1,X2) -> U22(X1,X2)
a__U31(X1,X2) -> U31(X1,X2)
a__U32(X1,X2) -> U32(X1,X2)
a__U41(X1,X2,X3) -> U41(X1,X2,X3)
a__U42(X1,X2,X3) -> U42(X1,X2,X3)
a__head(X) -> head(X)
a__afterNth(X1,X2) -> afterNth(X1,X2)
a__U51(X1,X2) -> U51(X1,X2)
a__U52(X1,X2) -> U52(X1,X2)
a__U61(X1,X2,X3,X4) -> U61(X1,X2,X3,X4)
a__U62(X1,X2,X3,X4) -> U62(X1,X2,X3,X4)
a__U63(X1,X2,X3,X4) -> U63(X1,X2,X3,X4)
a__U64(X1,X2) -> U64(X1,X2)
a__U71(X1,X2) -> U71(X1,X2)
a__U72(X1,X2) -> U72(X1,X2)
a__U81(X1,X2,X3) -> U81(X1,X2,X3)
a__U82(X1,X2,X3) -> U82(X1,X2,X3)
a__fst(X) -> fst(X)
a__natsFrom(X) -> natsFrom(X)
a__sel(X1,X2) -> sel(X1,X2)
a__tail(X) -> tail(X)
a__take(X1,X2) -> take(X1,X2)
)