#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

const int INF = INT_MAX / 8;

int main()
{
    vector<int> v(4);
    for(int i=0; i<4; ++i)
        cin >> v[i];

    int ret = INF;
    for(int a=1; a<=30; ++a){
        for(int b=1; b<a; ++b){
            for(int c=1; c<b; ++c){
                vector<int> x = {a, b, c};
                vector<int> dp(31, INF);
                dp[0] = 0;
                for(int i=0; i<30; ++i){
                    for(int j=0; j<3; ++j){
                        if(i + x[j] <= 30)
                            dp[i+x[j]] = min(dp[i+x[j]], dp[i] + 1);
                    }
                }

                int sum = 0;
                for(int i=0; i<4; ++i)
                    sum += dp[v[i]];
                ret = min(ret, sum);
            }
        }
    }
    cout << ret << endl;

    return 0;
}