(VAR u v x y )
(STRATEGY INNERMOST)
(RULES 
        minus(x,y) -> cond(ge(x,s(y)),x,y)
        cond(false,x,y) -> 0
        cond(true,x,y) -> s(minus(x,s(y)))
        ge(u,0) -> true
        ge(0,s(v)) -> false
        ge(s(u),s(v)) -> ge(u,v)
        
)