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)

#![allow(unused)]

#[allow(unused_imports)]
use std::{cmp, collections, fmt, io, iter, ops, str};
use cmp::Ordering::*;
use collections::{HashMap, HashSet};
use io::{Read, Write};

#[cfg(feature = "debug")]
macro_rules! debug {
    ($fmt: expr) => { eprintln!($fmt) };
    ($fmt: expr, $($arg: tt)*) => { eprintln!($fmt, $($arg)*) };
}

#[cfg(not(feature = "debug"))]
macro_rules! debug {
    ($fmt: expr) => {};
    ($fmt: expr, $($arg: tt)*) => {};
}

fn read_line() -> String {
    let mut buf = String::new();
    io::stdin().read_line(&mut buf).unwrap();
    buf.trim().to_owned()
}

fn read_word() -> String {
    const CAPACITY: usize = 16;

    let mut stdin = io::stdin();
    let mut byte: [u8; 1] = [0];

    loop {
        let mut buf = Vec::with_capacity(CAPACITY);

        loop {
            let res = stdin.read(&mut byte);

            if res.unwrap_or(0) == 0 || byte[0] <= b' ' {
                break;
            } else {
                buf.push(byte[0]);
            }
        }

        if buf.len() > 0 {
            return String::from_utf8(buf).unwrap();
        }
    }
}

fn parse_line<T: str::FromStr>() -> T {
    read_line().parse().ok().unwrap()
}

fn parse_word<T: str::FromStr>() -> T {
    read_word().parse().ok().unwrap()
}

fn parse_vec<T: str::FromStr>() -> Vec<T> {
    read_line()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

fn flush() {
    io::stdout().flush();
}

fn main() {
    let mut abc = parse_vec::<i32>();
    abc.sort();

    let c_b = abc[2] - abc[1];
    let c_a = abc[2] - abc[0];

    let cnt = c_b / 2 + c_a / 2 + match (c_b % 2, c_a % 2) {
        (0, 0) => 0,
        (0, 1) | (1, 0) => 2,
        (1, 1) => 1,
        _ => unreachable!(),
    };

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