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.

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.

Constraints

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

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

见题面 Input 部分

见题面 Output 部分