(VAR x y z )
(STRATEGY INNERMOST)
(RULES 
        f(c(c(a,y,a),b(x,z),a)) -> b(y,f(c(f(a),z,z)))
        f(b(b(x,f(y)),z)) -> c(z,x,f(b(b(f(a),y),y)))
        c(b(a,a),b(y,z),x) -> b(a,b(z,z))
        
)