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.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace A
{
    class Program
    {
        public static void Main(string[] args)
        {
            var s = ReadLineIntSpilit();
            Array.Sort(s);
            Console.WriteLine(s[0] == s[1] ? s[2] : s[0]);
            ReadLine();
        }

        /// <summary>
        /// stringを一文字ずつintにキャストして配列に変換します。
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public static int[] StringCharArrayIntArray(string str)
        {
            List<int> b = new List<int>();
            for (int i = 0; i < str.Length; i++) {
                b.Add( int.Parse(str[i].ToString()));
            }
            return b.ToArray();
        }

        public static string ReadLine()
        {
            return Console.ReadLine();
        }

        public static int ReadLineInt()
        {
            return int.Parse(Console.ReadLine());
        }

        public static string[] ReadLineStringSplit(char a = ' ')
        {
            return ReadLine().Split(a).ToArray();
        }

        public static int[] ReadLineIntSpilit(char a = ' ')
        {
            return ReadLine().Split(a).Select(x => int.Parse(x)).ToArray();
        }
    }
}