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 Perl6 (rakudo-star 2016.01) (judge verdict: Accepted)

use nqp;

my \a = $*IN.get.split(" ");
for <0 1 2> {
  if nqp::cmp_s(a[nqp::mod_n(nqp::unbox_i($_),nqp::unbox_i(3))],a[nqp::mod_n(nqp::unbox_i($_+1),nqp::unbox_i(3))]) == nqp::unbox_i(0) {
      nqp::say(a[nqp::mod_n(nqp::unbox_i($_+2),nqp::unbox_i(3))])
  }
}