Problem:
Score : 100 points

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

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

using System;
using System.Collections.Generic;
using System.Linq;

namespace atcoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var all = int.Parse(Console.ReadLine());
            var allSet = Console.ReadLine().Split(' ').Select(p => int.Parse(p)).ToList();

            if (allSet[0] == allSet[1])
                Console.WriteLine(allSet[2]);
            if (allSet[2] == allSet[1])
                Console.WriteLine(allSet[0]);
            else
                Console.WriteLine(allSet[1]);

        }
    }
}