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 (Clang 3.8.0) (judge verdict: Accepted)

#include<stdio.h>
int main()
{
  int a,b,n[4] = {0},i;
  scanf("%d%d",&a,&b);
  n[a]++,n[b]++;
  for(i = 1; i <= 3; i++)
    if(!n[i]) printf("%d\n",i);
  return 0;
}