(VAR L M N X Y )
(RULES 
        le(0, Y) -> true
        le(s(X), 0) -> false
        le(s(X), s(Y)) -> le(X, Y)
        app(nil, Y) -> Y
        app(cons(N, L), Y) -> cons(N, app(L, Y))
        low(N, nil) -> nil
        low(N, cons(M, L)) -> iflow(le(M, N), N, cons(M, L))
        iflow(true, N, cons(M, L)) -> cons(M, low(N, L))
        iflow(false, N, cons(M, L)) -> low(N, L)
        high(N, nil) -> nil
        high(N, cons(M, L)) -> ifhigh(le(M, N), N, cons(M, L))
        ifhigh(true, N, cons(M, L)) -> high(N, L)
        ifhigh(false, N, cons(M, L)) -> cons(M, high(N, L))
        quicksort(nil) -> nil
        quicksort(cons(N, L)) -> app(quicksort(low(N, L)), cons(N, quicksort(high(N, L))))
        
)