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>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define PI 				acos(-1)
#define mp				make_pair
#define pb				push_back
#define all(a)			(a).begin(), (a).end()
#define sz(a)			a.size()
#define srt(a)			sort(all(a))
#define mem(a, h)		memset(a, (h), sizeof(a))
#define f 				first
#define s 				second
#define MOD1			998244353
#define fore(i, b, e)	for(int i = b; i < e; i++)
#define forg(i, b, e, m)	for(int i = b; i < e; i+=m)
int in(){int r=0,c;for(c=getchar();c<=32;c=getchar());if(c=='-') return -in();for(;c>32;r=(r<<1)+(r<<3)+c-'0',c=getchar());return r;}

using namespace std;
using namespace __gnu_pbds;

typedef long long 		ll;
typedef unsigned long long 		ull;
typedef pair<int, int>  ii;
typedef vector<int>     vi;
typedef vector<ii>      vii;
typedef vector<ll>      vll;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//find_by_order kth largest  order_of_key <
const int tam = 100010;
const int MOD = 1e9+7;
const double EPS = 1e-9;

int main()
{
	ios::sync_with_stdio(0); cin.tie(0);
	//freopen("qwe.txt", "r", stdin);
	//freopen("asd.txt", "w", stdout);
	int a, b, c;
	cin>>a>>b>>c;
	int res = 0;
	if(a % 2 != b % 2 && a % 2 != c % 2)
	{
		b++;
		c++;
		res++;
	}
	if(a % 2 != b % 2 && b % 2 != c % 2)
	{
		a++;
		c++;
		res++;
	}
	if(c % 2 != b % 2 && a % 2 != c % 2)
	{
		a++;
		b++;
		res++;
	}
	int maxi = max(a, max(b, c));
	cout<< res + (3 * maxi - a - b - c) / 2<<'\n';
	return 0;
}

// read the question correctly (is y a vowel? what are the exact constraints?)
// look out for SPECIAL CASES (n=1?) and overflow (ll vs int?) ARRAY OUT OF BOUNDSS2