(VAR X Y l m n x y )
(RULES 
        max(0, n) -> n
        max(n, 0) -> n
        max(s(n), s(m)) -> s(max(n, m))
        min(0, n) -> 0
        min(n, 0) -> 0
        min(s(n), s(m)) -> s(min(n, m))
        insert(n, nil, X, Y) -> cons(n, nil)
        insert(n, cons(m, l), X, Y) -> cons(, insert(, l, X, Y))
        sort(nil, X, Y) -> nil
        sort(cons(n, l), X, Y) -> insert(n, sort(l, X, Y), X, Y)
        ascending_sort(l) -> sort(l, , )
        descending_sort(l) -> sort(l, , )
        
)