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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <stdio.h>

#define REP(i,n) for(int i=0;i<(n);i++)
#define RREP(i,n) for(int i=(n)-1;i>=0;i--)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define RFOR(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define STR(i,str) for(int i=0;(str)[i];i++)
#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIN(a,b) ((a)<(b)?(a):(b))
#define MAX3(a,b,c) ((a)>(b)?(a)>(c)?(a):(c):(b)>(c)?(b):(c))
#define MIN3(a,b,c) ((a)<(b)?(a)<(c)?(a):(c):(b)<(c)?(b):(c))
#define RNG(a,b) ((a)>(b)?(a)-(b):(b)-(a))
#define RNG3(a,b,c) ((a)>(b)?(b)>(c)?(a)-(c):(c)>(a)?(c)-(b):(a)-(b):(b)>(c)?(c)>(a)?(b)-(a):(b)-(c):(c)-(a))
#define MAXS(a,b) {if((a)<(b))(a)=(b);}
#define MINS(a,b) {if((a)>(b))(a)=(b);}

int main(){
	int a, b, c;
	scanf("%d%d%d", &a, &b, &c);
	if(a == b) printf("%d\n", c);
	else if(a == c) printf("%d\n", b);
	else printf("%d\n", a);
	return 0;
}