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::cmp;

fn main() {
    let mut abc = String::new();
    io::stdin().read_line(&mut abc).unwrap();
    let mut abc = abc.split_whitespace();
    let a: u32 = abc.next().unwrap().parse().unwrap();
    let b: u32 = abc.next().unwrap().parse().unwrap();
    let c: u32 = abc.next().unwrap().parse().unwrap();

    if a == b && b == c {
        println!("0");
    } else {
        let max = cmp::max(cmp::max(a, b), c);
        let tri_max = max * 3;
        let sum = a + b + c;

        let diff = tri_max - sum;
        let times = if diff % 2 == 0 { diff / 2 } else { (diff + 3) / 2 };
        println!("{}", times);
    }
}