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