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
fscanf(STDIN, "%d", $a);
fscanf(STDIN, "%d", $b);

$data_array = [1, 2, 3];

foreach ([$a, $b] as $num) {
  if(($key = array_search($num, $data_array)) !== false) {
      unset($data_array[$key]);
  }
}

foreach ($data_array as $result) {
  echo $result;
}