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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

// C.

#include <iostream>
#include <sstream>
#include <algorithm>

using namespace std;

int main(int argc, char *argv[]) {
	int x[3];
	cin >> x[0] >> x[1] >> x[2];
	int ans = 0;
	while (x[0] != x[1] || x[1] != x[2]) {
		++ans;
		sort(x, x + 3);
		if (x[1] - x[0] >= 2) {
			x[0] += 2;
		} else {
			x[0]++;
			x[1]++;
		}
	}
	cout << ans << endl;
	return 0;
}