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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

$arr = explode(' ', trim(fgets(STDIN)));
for ($i = 0; $i < 3; $i++) {
    $arr[$i] = (int)$arr[$i];
}
rsort($arr);

$k = intval(($arr[0] - $arr[1]) / 2) + ($arr[0] - $arr[1]) % 2;

$arr[2] += ($arr[0] - $arr[1]) % 2;

if (($arr[0] - $arr[2]) % 2 === 0) {
    $k += ($arr[0] - $arr[2]) / 2;
} else {
    $k += intval(($arr[0] - $arr[2]) / 2) + 2;
}

echo $k . PHP_EOL;