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)

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
#define REP(i,to) for(i=0;i<(to);i++)

int main() {
	int i, ans = 0;
	vector<int> a(3);

	REP(i, 3) 
		cin >> a[i];
	sort(a.begin(), a.end(), greater<int>());

	while (a[0] != a[1]) {
		a[1]++; a[2]++; ans++;
	}
	while (1) {
		if (a[0] == a[2]) break;
		if (a[0] - a[2] == 1) {
			ans += 2;
			break;
		}
		a[2] += 2;
		ans++;
	}
	cout << ans << endl;
	return 0;
}