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::FromStr;
use std::cmp::{min, max};
use std::rc::Rc;
use std::mem::swap;

fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin_lock = stdin.lock();
    let s = stdin_lock
        .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().unwrap()
}

static DX: &'static [i32] = &[0, 0, 1, -1];
static DY: &'static [i32] = &[1, -1, 0, 0];


fn main() {
    let x: Vec<i32> = (0..3).map(|_| read::<i32>()).collect();

    let m = x.iter().max().unwrap();

    let mut ans = 0;
    let mut cnt = 0;

    for n in x.iter() {
        ans += (m - n) / 2;

        if (m - n) % 2 != 0 {
            cnt += 1;
        }
    }

    ans += cnt / 2;

    if cnt % 2 != 0 {
        ans += (x.len() as i32 + 1) / 2;
    }

    println!("{}", ans);
}