(VAR x y )
(RULES 
        le(0, y) -> true
        le(s(x), 0) -> false
        le(s(x), s(y)) -> le(x, y)
        minus(0, y) -> 0
        minus(s(x), y) -> if_minus(le(s(x), y), s(x), y)
        if_minus(true, s(x), y) -> 0
        if_minus(false, s(x), y) -> s(minus(x, y))
        quot(0, s(y)) -> 0
        quot(s(x), s(y)) -> s(quot(minus(x, y), s(y)))
        log(s(0)) -> 0
        log(s(s(x))) -> s(log(s(quot(x, s(s(0))))))
        
)