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::io::{BufRead, Write};

fn solve<R: BufRead, W: Write>(mut input: R, mut output: W) {
    let mut buf = String::new();
    input.read_line(&mut buf).unwrap();
    let (a, b, c): (usize, usize, usize) = {
        let mut split = buf.split_whitespace();
        (
            split.next().unwrap().parse().unwrap(),
            split.next().unwrap().parse().unwrap(),
            split.next().unwrap().parse().unwrap(),
        )
    };
    let max = *[a, b, c].iter().max().unwrap();
    let rem = max * 3 - a - b - c;
    let result = if rem % 2 == 1 { rem + 3 } else { rem } / 2;
    writeln!(output, "{}", result).unwrap();
}

fn main() {
    let stdin = io::stdin();
    let stdout = io::stdout();
    solve(stdin.lock(), stdout.lock());
}

#[cfg(test)]
mod tests {
    fn test(input: &str, output: &str) {
        let mut v: Vec<u8> = Vec::new();
        ::solve(input.as_bytes(), &mut v);
        assert_eq!(String::from_utf8(v).unwrap(), output);
    }

    #[test]
    fn case1() {
        test(
            "2 5 4
",
            "2\n",
        );
    }

    #[test]
    fn case2() {
        test(
            "2 6 3
",
            "5\n",
        );
    }

    #[test]
    fn case3() {
        test(
            "31 41 5
",
            "23\n",
        );
    }
}