(VAR x y )
(STRATEGY INNERMOST)
(RULES 
        minus(minus(x)) -> x
        minus(+(x,y)) -> *(minus(minus(minus(x))),minus(minus(minus(y))))
        minus(*(x,y)) -> +(minus(minus(minus(x))),minus(minus(minus(y))))
        f(minus(x)) -> minus(minus(minus(f(x))))
        
)