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: Accepted)

using System;
using System.Reflection;
using System.Linq.Expressions;
using System.Linq;
using System.IO;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;

namespace AtCoder {
    public class Program {
        static int[] getKeys(char delimiter) {
            var Keys = Console.ReadLine().Split(' ');
            int[] Ns = new int[Keys.Length];
            for (int i = 0; i < Keys.Length; i++) {
                Ns[i] = int.Parse(Keys[i]);
            }
            return Ns;
        }

        static void Main() {
            var Keys = getKeys(' ');
            if (Keys[0] == Keys[1]) {
                Console.WriteLine(Keys[2]);
            } else if (Keys[1] == Keys[2]) {
                Console.WriteLine(Keys[0]);
            } else {
                Console.WriteLine(Keys[1]);
            }
        }
    }
}