(VAR x y z )
(RULES 
        D(t) -> s(h)
        D(constant) -> h
        D(b(x, y)) -> b(D(x), D(y))
        D(c(x, y)) -> b(c(y, D(x)), c(x, D(y)))
        D(m(x, y)) -> m(D(x), D(y))
        D(opp(x)) -> opp(D(x))
        D(div(x, y)) -> m(div(D(x), y), div(c(x, D(y)), pow(y, 2)))
        D(ln(x)) -> div(D(x), x)
        D(pow(x, y)) -> b(c(c(y, pow(x, m(y, 1))), D(x)), c(c(pow(x, y), ln(x)), D(y)))
        b(h, x) -> x
        b(x, h) -> x
        b(s(x), s(y)) -> s(s(b(x, y)))
        b(b(x, y), z) -> b(x, b(y, z))
        
)