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<cstdio>
#include<cstring>
#include<cmath>
#include<bitset>
#include<iostream>
#include<algorithm>
#include<string>
#include<utility>
#include<tuple>
#include<vector>
#include<list>
#include<map>
#include<queue>
#include<stack>
#include<numeric>
#include<functional>

#define IOS ios::sync_with_stdio(false),cin.tie(0)
#define REP(i,n) for(int i = 0;i < n;i++)
#define MEM(a,b) memset(a,b,sizeof(a))

using namespace std;

typedef long long ll;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;

int main() {
	int a[3];
	REP(i, 3)cin >> a[i];
	sort(a, a + 3);
	int ans = 0;
	ans += a[2] - a[1];
	if ((a[1] - a[0]) % 2 == 0) {
		ans += (a[1] - a[0]) / 2;
	}
	else {
		ans += (a[1] - a[0] + 1) / 2;
		ans++;
	}
	cout << ans << endl;
}