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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php

  $select = [1, 2, 3];

  $a = trim(fgets(STDIN));
  $b = trim(fgets(STDIN));
  
  $ans = array_values(array_diff($select, array($a, $b)));

  echo $ans[0];