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 (1.42.0) (judge verdict: Accepted)

use std::io::*;
use std::str::*;

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

fn usize() -> usize {
    read()
}

fn vec_usize(n: usize) -> Vec<usize> {
    let mut vec = Vec::new();
    for _ in 0..n {
        vec.push(usize())
    }
    vec
}

fn main() {
    let abc = vec_usize(3);
    let mut a = abc[0];
    let mut b = abc[1];
    let mut c = abc[2];

    let mut count = 0;
    while !(a == b && b == c) {
        if a < b && a < c {
            a += 2;
            count += 1;
            continue;
        }
        if b < a && b < c {
            b += 2;
            count += 1;
            continue;
        }
        if c < a && c < b {
            c += 2;
            count += 1;
            continue;
        }
        if a == b {
            a += 1;
            b += 1;
            count += 1;
            continue;
        }
        if b == c {
            b += 1;
            c += 1;
            count += 1;
            continue;
        }
        if c == a {
            c += 1;
            a += 1;
            count += 1;
            continue;
        }
    }
    println!("{}", count);
}