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 PHP (5.6.30) (judge verdict: Accepted)

<?php

$input = explode(' ', trim(fgets(STDIN)));
$a = intval($input[0]);
$b = intval($input[1]);
$c = intval($input[2]);

$count = 0;
while ($a != $b || $a != $c || $b != $c) {
    $count++;

    if ($a == $b) {
        if ($c < $a) {
            $c += 2;
            continue;
        } else {
            $a += 1;
            $b += 1;
            continue;
        }
    }

    if ($a == $c) {
        if ($b < $a) {
            $b += 2;
            continue;
        } else {
            $a += 1;
            $c += 1;
            continue;
        }
    }

    if ($b == $c) {
        if ($a < $b) {
            $a += 2;
            continue;
        } else {
            $b += 1;
            $c += 1;
            continue;
        }
    }

    if ($a > $b && $a > $c) {
        $b += 1;
        $c += 1;
    }
    if ($b > $a && $b > $c) {
        $a += 1;
        $c += 1;
    }
    if ($c > $a && $c > $b) {
        $a += 1;
        $b += 1;
    }
}
echo $count;