(VAR x y )
(STRATEGY INNERMOST)
(RULES 
        leq(0,y) -> true
        leq(s(x),0) -> false
        leq(s(x),s(y)) -> leq(x,y)
        if(true,x,y) -> x
        if(false,x,y) -> y
        -(x,0) -> x
        -(s(x),s(y)) -> -(x,y)
        mod(0,y) -> 0
        mod(s(x),0) -> 0
        mod(s(x),s(y)) -> if(leq(y,x),mod(-(s(x),s(y)),s(y)),s(x))
        
)