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 Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.stream.IntStream;

public class Main {

	/** 入力数字の数 */
	private static final int N = 3;

	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			Map<Integer, Integer> map = new HashMap<>();
			IntStream.range(0, N).forEach(i -> {
				int a = scanner.nextInt();
				map.put(a, map.getOrDefault(a, 0) + 1);
			});
			System.out
					.println(map.entrySet().stream().filter(entry -> entry.getValue() == 1).findFirst().get().getKey());
		}
	}
}