(VAR x y z )
(RULES 
        b(a, b(c(z, x, y), a)) -> b(b(z, c(y, z, a)), x)
        f(c(a, b(b(z, a), y), x)) -> f(c(x, b(z, x), y))
        c(f(c(a, y, a)), x, z) -> f(b(b(z, z), f(b(y, b(x, a)))))
        
)