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 Rust (1.15.1) (judge verdict: Accepted)

fn read_line(s: &mut String) -> &str {
  std::io::stdin().read_line(s).unwrap();
  s.trim()
}

fn main() {
  let mut tmp = String::new();
  let ary: Vec<isize> = read_line(&mut tmp).split(" ").map(|n| n.parse().unwrap()).collect();
  let part1: Vec<&isize> = ary.iter().filter(|n| *n == &ary[0]).collect();
  let part2: Vec<&isize> = ary.iter().filter(|n| *n != &ary[0]).collect();
  let ans = if part1.len() == 2 {
    part2[0]
  } else {
    part1[0]
  };
  println!("{}", ans);
}