(GOAL COMPLEXITY)
(STARTTERM CONSTRUCTORBASED)
(VAR X )
(STRATEGY INNERMOST)
(RULES 
        f(a, a) -> f(a, b)
        f(a, b) -> f(s(a), c)
        f(s(X), c) -> f(X, c)
        f(c, c) -> f(a, a)
        
)