Problem:
Score: 100 points

Problem Statement

Takahashi is solving quizzes. He has easily solved all but the last one.

The last quiz has three choices: 1, 2, and 3.

With his supernatural power, Takahashi has found out that the choices A and B are both wrong.

Print the correct choice for this problem.

Constraints

Each of the numbers A and B is 1, 2, or 3.

A and B are different.

Input

Input is given from Standard Input in the following format:

A
B

Output

Print the correct choice.

Sample Input 1

3
1

Sample Output 1

2

When we know 3 and 1 are both wrong, the correct choice is 2.

Sample Input 2

1
2

Sample Output 2

3

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
internal class Program
    {
        public static void Main(string[] args)
        {
            bool[] x = new bool[3];
            var num1 = Convert.ToInt32(Console.ReadLine());
            var num2 = Convert.ToInt32(Console.ReadLine());
            x[num1-1] = true;
            x[num2-1] = true;
            
            var t = Array.FindIndex(x,  b => b == false);
            Console.WriteLine(t+1);
        }
    }