(VAR x y z )
(RULES 
        h(z, e(x)) -> h(c(z), d(z, x))
        d(z, g(0, 0)) -> e(0)
        d(z, g(x, y)) -> g(e(x), d(z, y))
        d(c(z), g(g(x, y), 0)) -> g(d(c(z), g(x, y)), d(z, g(x, y)))
        g(e(x), e(y)) -> e(g(x, y))
        
)