(VAR YS X XS Y L X1 X2)
(RULES 
active(app(nil,YS)) -> mark(YS)
active(app(cons(X,XS),YS)) -> mark(cons(X,app(XS,YS)))
active(from(X)) -> mark(cons(X,from(s(X))))
active(zWadr(nil,YS)) -> mark(nil)
active(zWadr(XS,nil)) -> mark(nil)
active(zWadr(cons(X,XS),cons(Y,YS))) -> mark(cons(app(Y,cons(X,nil)),zWadr(XS,YS)))
active(prefix(L)) -> mark(cons(nil,zWadr(L,prefix(L))))
mark(app(X1,X2)) -> active(app(mark(X1),mark(X2)))
mark(nil) -> active(nil)
mark(cons(X1,X2)) -> active(cons(mark(X1),X2))
mark(from(X)) -> active(from(mark(X)))
mark(s(X)) -> active(s(mark(X)))
mark(zWadr(X1,X2)) -> active(zWadr(mark(X1),mark(X2)))
mark(prefix(X)) -> active(prefix(mark(X)))
app(mark(X1),X2) -> app(X1,X2)
app(X1,mark(X2)) -> app(X1,X2)
app(active(X1),X2) -> app(X1,X2)
app(X1,active(X2)) -> app(X1,X2)
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)
from(mark(X)) -> from(X)
from(active(X)) -> from(X)
s(mark(X)) -> s(X)
s(active(X)) -> s(X)
zWadr(mark(X1),X2) -> zWadr(X1,X2)
zWadr(X1,mark(X2)) -> zWadr(X1,X2)
zWadr(active(X1),X2) -> zWadr(X1,X2)
zWadr(X1,active(X2)) -> zWadr(X1,X2)
prefix(mark(X)) -> prefix(X)
prefix(active(X)) -> prefix(X)
)