(VAR x y )
(STRATEGY INNERMOST)
(RULES 
        -(x,0) -> x
        -(s(x),s(y)) -> -(x,y)
        +(0,y) -> y
        +(s(x),y) -> s(+(x,y))
        *(x,0) -> 0
        *(x,s(y)) -> +(x,*(x,y))
        p(s(x)) -> x
        f(s(x)) -> f(-(p(*(s(x),s(x))),*(s(x),s(x))))
        
)