(GOAL COMPLEXITY)
(STARTTERM CONSTRUCTORBASED)
(VAR x x1 x2 y )
(STRATEGY INNERMOST)
(RULES 
        g(S(x), y) -> g(x, S(y))
        f(y, S(x)) -> f(S(y), x)
        g(0, x2) -> x2
        f(x1, 0) -> g(x1, 0)
        
)