MAYBE

Problem:
 0(0(1(2(1(x1))))) -> 0(2(3(4(x1))))
 1(4(5(3(2(x1))))) -> 1(5(0(5(x1))))
 3(0(2(3(0(x1))))) -> 5(0(2(1(1(x1)))))
 0(1(5(2(3(2(x1)))))) -> 0(5(3(1(3(2(x1))))))
 1(3(0(4(1(4(x1)))))) -> 1(2(0(1(2(x1)))))
 3(5(4(4(1(1(x1)))))) -> 0(2(3(0(4(x1)))))
 4(5(5(4(5(5(x1)))))) -> 4(3(1(5(1(5(x1))))))
 1(3(2(5(2(3(1(x1))))))) -> 1(0(5(1(3(4(x1))))))
 3(2(1(2(5(4(3(1(x1)))))))) -> 2(5(0(4(4(3(5(x1)))))))
 2(4(2(3(0(3(4(5(2(x1))))))))) -> 2(4(0(0(0(0(0(5(2(x1)))))))))
 3(4(2(4(0(2(1(0(2(x1))))))))) -> 3(1(0(5(0(5(0(1(x1))))))))
 2(4(2(0(3(4(0(3(3(1(x1)))))))))) -> 3(5(2(0(5(3(3(2(2(x1)))))))))
 0(0(4(2(0(3(4(5(2(0(0(0(0(0(x1)))))))))))))) -> 2(4(1(2(4(4(3(2(5(2(3(5(5(0(x1))))))))))))))
 3(2(3(2(2(0(4(5(0(3(5(3(4(4(5(x1))))))))))))))) ->
 5(2(3(5(2(1(4(4(1(5(5(3(0(1(4(2(x1))))))))))))))))
 2(4(0(1(1(5(0(2(0(5(2(3(5(4(0(2(x1)))))))))))))))) ->
 5(0(2(0(2(0(2(5(4(0(0(5(5(2(0(x1)))))))))))))))
 3(0(4(5(3(5(0(3(5(2(3(1(5(4(2(1(x1)))))))))))))))) ->
 2(5(3(3(2(3(0(2(5(4(0(2(4(5(2(1(x1))))))))))))))))
 3(5(3(2(4(3(3(1(0(0(5(4(0(2(1(1(x1)))))))))))))))) ->
 3(5(3(3(3(2(5(4(1(5(5(1(3(5(1(x1)))))))))))))))
 3(1(5(3(2(4(2(2(4(3(4(2(3(4(5(1(4(4(5(x1))))))))))))))))))) ->
 3(4(3(2(2(4(1(2(1(3(3(0(0(3(3(4(2(4(x1))))))))))))))))))
 4(5(3(3(0(5(2(0(3(5(0(3(3(2(3(1(3(3(4(x1))))))))))))))))))) ->
 4(0(4(1(5(1(4(2(4(2(5(4(1(2(5(2(1(2(5(2(2(x1)))))))))))))))))))))
 0(3(5(0(0(0(4(1(2(1(3(5(5(5(0(3(5(0(3(4(x1)))))))))))))))))))) ->
 0(3(5(3(3(2(4(5(5(4(0(2(3(0(2(5(2(4(3(4(x1))))))))))))))))))))
 0(4(2(4(3(5(4(2(5(1(4(3(2(5(3(5(4(2(3(0(x1)))))))))))))))))))) ->
 5(2(3(3(4(1(5(3(2(2(3(5(1(1(1(2(1(2(2(1(x1))))))))))))))))))))
 2(2(2(3(5(5(2(1(4(1(2(2(1(5(2(1(1(0(2(2(x1)))))))))))))))))))) ->
 2(3(2(3(2(5(4(2(0(3(2(0(2(4(5(2(4(4(x1))))))))))))))))))
 3(3(2(0(2(2(5(3(2(3(3(1(3(5(5(1(3(0(2(1(x1)))))))))))))))))))) ->
 3(0(5(1(1(3(2(1(2(5(5(4(3(4(3(0(5(5(3(4(x1))))))))))))))))))))
 0(4(5(4(0(3(1(4(4(0(3(4(2(5(4(1(0(0(5(1(2(x1))))))))))))))))))))) ->
 3(5(4(4(4(5(5(0(2(4(4(1(5(2(1(2(5(2(5(2(2(x1)))))))))))))))))))))
 4(4(1(5(4(1(1(2(1(5(1(1(4(4(2(2(4(2(4(5(3(x1))))))))))))))))))))) ->
 0(3(2(3(2(0(3(2(1(1(4(5(2(2(0(1(1(2(3(x1)))))))))))))))))))

Proof:
 Open