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 Python (3.4.3) (judge verdict: Accepted)

"""
Atcoder_Beginner_Contest_148
A
"""
import sys
input = sys.stdin.readline
sys.setrecursionlimit(10000)

ans = [1,2,3]
A = int(input())
B = int(input())
result = set(ans) - set([A,B])

print(result.pop())