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 Scala (2.11.7) (judge verdict: Accepted)

import scala.io._

// e.g
// 1 2 3
// val Array(a, b) = readLine.split(" ").map(_.toInt) => Array(1, 2, 3)
// 5
// 1 2 3
// 4 5 6
// 7 8 9
// val lines = Source.stdin.getLines()
// データ個数読み取り
// val n = lines.next().toInt
// データ行n個読み取り
// val data = lines.take(n).map{ line => line.split(" ").map(_.toInt).toList }.toList => List(List(1, 2, 3), List(4, 5, 6), List(7, b, 9))

object Main {
  def main(args: Array[String]): Unit = {
    val Array(a, b, c) = readLine.split(" ").map(_.toInt)
    if (a == b) {
      println(c)
    }
    else if (b == c) {
      println(a)
    }
    else {
      println(b)
    }
  }
}