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: Runtime Error)

use std::io::*;

fn main() {
    let a = read();
    let b = read();
    let c = read();

	let mut ans = 0;
	if a == b {
		ans = c;
	} else if a == c {
		ans = b;
	} else {
		ans = a;
	}
    println!("{}", ans);
}

fn read() -> usize {
    let s = stdin();
    let b = s.bytes()
        .map(|c| c.unwrap() as char)
        .take_while(|c| !c.is_whitespace())
        .collect::<String>();
    b.parse().ok().unwrap()
}