(VAR x y )
(RULES 
        cond(true, x, y) -> cond(gr(x, y), x, add(x, y))
        gr(0, x) -> false
        gr(s(x), 0) -> true
        gr(s(x), s(y)) -> gr(x, y)
        add(0, x) -> x
        add(s(x), y) -> s(add(x, y))
        
)