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.

Examples

Input

5 7 5


Output

7


Input

1 1 7


Output

7


Input

-100 100 100


Output

-100
#include<iostream>
using namespace std;
int main(){
 int a,b,c,d;
 cin>>a>>b>>c;
 if(a==b){
 d=c;
 }
 else if(a==c){
 d=b;
 }
 else if(b==c){
 d=a;
 }
 cout<<d;
}