(VAR x y z )
(RULES 
        g(x,y) -> x
        g(x,y) -> y
        f(0,1,x) -> f(s(x),x,x)
        f(x,y,s(z)) -> s(f(0,1,z))
        rand(x) ->= x
        rand(x) ->= rand(s(x))
)