Chinchirorin

Source: AtCoder

Problem Statement

Three dice show $a,b,c$. If two values are equal, print the remaining value. If all three are pairwise different, print $0$. If all three are equal, the answer is that common value.

Input

One line contains $a$, $b$, and $c$.

Output

Print the result according to the rule above.

Subtasks

• Subtask 1 (100%): $1 \le a,b,c \le 6$

Examples

Example 1

Input

2 5 2

Output

5

Explanation

For the sample values 2, 5, 2, evaluating the conditions in the statement gives 5. Therefore the program prints the shown output.

Example 2

Input

4 5 6

Output

0

Explanation

For the sample values 4, 5, 6, evaluating the conditions in the statement gives 0. Therefore the program prints the shown output.

Example 3

Input

1 1 1

Output

1

Explanation

For the sample values 1, 1, 1, evaluating the conditions in the statement gives 1. Therefore the program prints the shown output.