(VAR x y z )
(STRATEGY INNERMOST)
(RULES 
        min(x,0) -> 0
        min(0,y) -> 0
        min(s(x),s(y)) -> s(min(x,y))
        max(x,0) -> x
        max(0,y) -> y
        max(s(x),s(y)) -> s(max(x,y))
        minus(x,0) -> x
        minus(s(x),s(y)) -> s(minus(x,y))
        gcd(s(x),s(y)) -> gcd(minus(max(x,y),min(x,transform(y))),s(min(x,y)))
        transform(x) -> s(s(x))
        transform(cons(x,y)) -> cons(cons(x,x),x)
        transform(cons(x,y)) -> y
        transform(s(x)) -> s(s(transform(x)))
        cons(x,y) -> y
        cons(x,cons(y,s(z))) -> cons(y,x)
        cons(cons(x,z),s(y)) -> transform(x)
        
)