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