#include <iostream>
#include <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()
#define INF 1<<20

/*

	No.27 板の準備

	全探索、DP？
*/
using namespace std;

typedef long long ll;
typedef pair<int, int> P;
const int MAX_N = 35;
int dp[MAX_N];

int main()
{
	ios_base::sync_with_stdio(0);
	vector<int> V(4, 0 );
	rep (i, 4 ) cin >> V[i];
	int a[3] = {0};
	int res = INF;
	for (a[0] = 1; a[0] < MAX_N; a[0]++ ){
		for (a[1] = a[0] + 1; a[1] < MAX_N; a[1]++ ){
			for (a[2] = a[1] + 1; a[2] < MAX_N; a[2]++ ){
				fill (dp, dp+MAX_N, INF );
				dp[0] = 0;
				rep (k, 3 )
					for (int j = a[k]; j < MAX_N; j++ )
						dp[j] = min (dp[j], dp[j-a[k]] + 1 );
				int curr = 0;
				rep (i, 4 ) curr += dp[V[i]];
				res = min (res, curr );
			} // end for
		} // end for
	} // end for

	cout << res << endl;

	return 0;
}