#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <cstdlib>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional> 
#include <iomanip>
#include <unordered_map>
#include <memory.h>
#include <unordered_set>
#include <fstream>
#include <random>

using namespace std;

int dp[31];

int main(void)
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	
	int a, b, c, d;
	int res = 1e9;
	cin >> a >> b >> c >> d;

	for (int i = 1; i <= 30; i++)
	{
		for (int j = i + 1; j <= 30; j++)
		{
			for (int k = j + 1; k <= 30; k++)
			{
				for (int l = 0; l <= 30; l++)
				{
					dp[l] = 1e5;
				}
				dp[i] = 1;
				dp[j] = 1;
				dp[k] = 1;
				for (int x = 1; x <= 30; x++)
				{
					if (dp[x] != 1e5) continue;
					for (int y = 1; y < x; y++)
					{
						dp[x] = min(dp[x], dp[y] + dp[x - y]);
					}
				}
				res = min(res, dp[a] + dp[b] + dp[c] + dp[d]);
			}
		}
	}

	cout << res << '\n';

	return 0;
}