#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <queue>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>

using namespace std;

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef long long LL;
typedef unsigned long long ULL;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)

#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(auto i: c)
#define SORT(c) sort((c).begin(),(c).end())

#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()

const double EPS = 1e-10;
const double PI  = acos(-1.0);

#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int V0, V1, V2, V3;
	cin >> V0 >> V1 >> V2 >> V3;

	int ret = 1000;
	FOR(A, 1, 31){
		FOR(B, A, 31){
			FOR(C, B, 31){
				int dp[31];
				REP(i, 31) dp[i] = 1000;
				dp[0] = 0;
				REP(i, 31){
					function<void(int)> f = [&](int n){
						if(i + n < 31) dp[i + n] = min(dp[i + n], dp[i] + 1);
					};
					f(A);
					f(B);
					f(C);
				}
				ret = min(ret, dp[V0] + dp[V1] + dp[V2] + dp[V3]);
			}
		}
	}

	cout << ret << endl;

	return 0;
}