(VAR x1 )
(RULES 
        a(b(c(a(x1)))) -> b(a(c(b(a(b(x1))))))
        a(d(x1)) -> c(x1)
        a(f(f(x1))) -> g(x1)
        b(g(x1)) -> g(b(x1))
        c(x1) -> f(f(x1))
        c(a(c(x1))) -> b(c(a(b(c(x1)))))
        c(d(x1)) -> a(a(x1))
        g(x1) -> c(a(x1))
        g(x1) -> d(d(d(d(x1))))
        
)