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 <bits/stdc++.h>
using namespace std;

const int maxn=100;

bool vis[maxn][maxn][maxn];
int ans;
int a, b, c, maxnum;

void dfs(int a, int b, int c, int s)
{
	if (s>=ans) return;
	if (a>maxnum || b>maxnum || c>maxnum) return;
	if (vis[a][b][c]) return;
	if (a==b && a==c)
	{
		ans=s;
		return;
	}
	vis[a][b][c]=true;
	dfs(a+2, b, c, s+1);
	dfs(a, b+2, c, s+1);
	dfs(a, b, c+2, s+1);
	dfs(a+1, b+1, c, s+1);
	dfs(a+1, b, c+1, s+1);
	dfs(a, b+1, c+1, s+1);
}
int main()
{
	scanf("%d%d%d", &a, &b, &c);
	maxnum=max(a, max(b, c))+10;
	ans=0x3fffffff;
	dfs(a, b, c, 0);
	printf("%d\n", ans);
	return 0;
}