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.