#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
//#define int long long
using namespace std;

#define INF 999999

int A, B, C;
int dp[31];
int V0, V1, V2, V3;

int rec(int Vi)
{
	//printf("A = %d, B = %d, C = %d\n", A, B, C);
	if (dp[Vi] != -1) return dp[Vi];

	if (A == Vi || B == Vi || C == Vi) return dp[Vi] = 1;
	
	int ret = INF;
	for (int i=1; i<=Vi-1; i++)
	{
		ret = min(ret, rec(i) + rec(Vi-i));
	}
	
	return dp[Vi] = ret;
}

signed main()
{
	//rep(i,31) dp[i] = -1;

	cin >> V0 >> V1 >> V2 >> V3;

/*
	A = 28; B = 29; C = 30;
	printf("rec(%d) = %d\n", V0, rec(V0));
	printf("rec(%d) = %d\n", V1, rec(V1));
	printf("rec(%d) = %d\n", V2, rec(V2));
	printf("rec(%d) = %d\n", V3, rec(V3));
*/

	int ans = INF;
	for (A=1; A<=30; A++)
	{
		for (B=1; B<=30; B++)
		{
			for (C=1; C<=30; C++)
			{
				rep(i,31) dp[i] = -1;
				ans = min(ans, rec(V0) + rec(V1) + rec(V2) + rec(V3));
			}
		}
	}

	cout << ans << endl;
}