(VAR b x y )
(STRATEGY INNERMOST)
(RULES 
        minus(x,x) -> 0
        minus(s(x),s(y)) -> minus(x,y)
        minus(0,x) -> 0
        minus(x,0) -> x
        div(s(x),s(y)) -> s(div(minus(x,y),s(y)))
        div(0,s(y)) -> 0
        f(x,0,b) -> x
        f(x,s(y),b) -> div(f(x,minus(s(y),s(0)),b),b)
        
)