(GOAL COMPLEXITY)
(STARTTERM CONSTRUCTORBASED)
(VAR x y )
(STRATEGY INNERMOST)
(RULES 
        f(x, a(b(y))) -> f(c(d(x)), y)
        f(c(x), y) -> f(x, a(y))
        f(d(x), y) -> f(x, b(y))
        
)