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::*;
use std::str::*;
use std::cmp;

fn read<T: FromStr>(s: &mut StdinLock) -> Option<T> {
    let s = s.by_ref()
        .bytes()
        .map(|c| c.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect::<String>();
    s.parse::<T>().ok()
}

fn main() {
    let s = stdin();
    let mut s = s.lock();
    let a: i32 = read(&mut s).unwrap();
    let b: i32 = read(&mut s).unwrap();
    let c: i32 = read(&mut s).unwrap();

    let large = cmp::max(cmp::max(a, b), c);
    let small = cmp::min(cmp::min(a, b), c);
    let middle = (a + b + c) - (large + small);

    let diff1 = large - middle;
    let diff2 = middle - small;

    if (diff2 % 2) == 0 {
        println!("{}", diff1 + diff2 / 2);
    } else {
        println!("{}", diff1 + diff2 / 2 + 2);
    }
}