(VAR x1 )
(RULES 
        a(b(x1)) -> C(x1)
        b(c(x1)) -> A(x1)
        c(a(x1)) -> B(x1)
        A(C(x1)) -> b(x1)
        C(B(x1)) -> a(x1)
        B(A(x1)) -> c(x1)
        a(a(a(a(a(x1))))) -> A(A(A(x1)))
        A(A(A(A(x1)))) -> a(a(a(a(x1))))
        b(b(b(b(b(x1))))) -> B(B(B(x1)))
        B(B(B(B(x1)))) -> b(b(b(b(x1))))
        c(c(c(c(c(x1))))) -> C(C(C(x1)))
        C(C(C(C(x1)))) -> c(c(c(c(x1))))
        B(a(a(a(a(x1))))) -> c(A(A(A(x1))))
        A(A(A(b(x1)))) -> a(a(a(a(C(x1)))))
        C(b(b(b(b(x1))))) -> a(B(B(B(x1))))
        B(B(B(c(x1)))) -> b(b(b(b(A(x1)))))
        A(c(c(c(c(x1))))) -> b(C(C(C(x1))))
        C(C(C(a(x1)))) -> c(c(c(c(B(x1)))))
        a(A(x1)) -> x1
        A(a(x1)) -> x1
        b(B(x1)) -> x1
        B(b(x1)) -> x1
        c(C(x1)) -> x1
        C(c(x1)) -> x1
        
)