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 (Clang 3.8.0) (judge verdict: Accepted)

#include <stdio.h>

int main(void)
{
  int a[3];
  int n1, n2;
  int c1, c2;
  int i;

  c1 = 0; c2 = 0;
  n1 = -200; n2 = -200;

  for ( i=0; i<3; i++ ) {
    scanf("%d", &a[i]);
    if ( n1 == -200 ) {
      n1 = a[i];
      c1 = 1;
    } else if ( n1 == a[i] ) {
      c1 = 2;
    } else if ( n2 == -200 ) {
      n2 = a[i];
      c2 = 1;
    } else if ( n2 == a[i] ) {
      c2 = 2;
    }
  }
  
  if ( c1 == 2 ) {
    printf("%d\n", n2);
  } else {
    printf("%d\n", n1);
  }
  return 0;
}