Problem:
Score : 300 points

Problem Statement

You are given three integers A, B and C. Find the minimum number of operations required to make A, B and C all equal by repeatedly performing the following two kinds of operations in any order:

Choose two among A, B and C, then increase both by 1.

Choose one among A, B and C, then increase it by 2.

It can be proved that we can always make A, B and C all equal by repeatedly performing these operations.

Constraints

0 \leq A,B,C \leq 50

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B C

Output

Print the minimum number of operations required to make A, B and C all equal.

Sample Input 1

2 5 4

Sample Output 1

2

We can make A, B and C all equal by the following operations:

Increase A and C by 1. Now, A, B, C are 3, 5, 5, respectively.

Increase A by 2. Now, A, B, C are 5, 5, 5, respectively.

Sample Input 2

2 6 3

Sample Output 2

5

Sample Input 3

31 41 5

Sample Output 3

23

Solution in Rust (1.15.1) (judge verdict: Accepted)

use std::io::{stdin, Read};
use std::str::FromStr;

// https://qiita.com/tubo28/items/e6076e9040da57368845
fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}

#[allow(dead_code)]
fn main() {
    let a = read::<usize>();
    let b = read::<usize>();
    let c = read::<usize>();

    let mut v = vec![a, b, c];
    v.sort();
    let mut a = v[0];
    let mut b = v[1];
    let c = v[2];

    let mut ans = 0;
    ans += (c - a) / 2;
    ans += (c - b) / 2;
    a += ((c - a) / 2) * 2;
    b += ((c - b) / 2) * 2;

    let mut v = vec![a, b, c];
    v.sort();

    let mut a = v[0];
    let mut b = v[1];
    let mut c = v[2];

    c -= a;
    b -= a;
    a -= a;

    match (a, b, c) {
        (0, 0, 0) => println!("{}", ans),
        (0, 0, 1) => println!("{}", ans + 1),
        (0, 1, 1) => println!("{}", ans + 2),
        _ => panic!("{} {} {}", a, b, c),
    }
}