Problem Statement

You are given three integers, $A$, $B$ and $C$.
Among them, two are the same, but the remaining one is different from the rest.
For example, when $A=5,B=7,C=5$, $A$ and $C$ are the same, but $B$ is different.
Find the one that is different from the rest among the given three integers.

Constraints

• $\-100 \\leq A,B,C \\leq 100$
• $A$, $B$ and $C$ are integers.
• The input satisfies the condition in the statement.

Input

Input is given from Standard Input in the following format:

$A$ $B$ $C$

Output

Among $A$, $B$ and $C$, print the integer that is different from the rest.

Sample Input 1

5 7 5

Sample Output 1

7

This is the same case as the one in the statement.

Sample Input 2

1 1 7

Sample Output 2

7

In this case, $C$ is the one we seek.

Sample Input 3

-100 100 100

Sample Output 3

-100