#include <bits/stdc++.h>

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 RANGE(vec) (vec).begin(),(vec).end()

using namespace std;


class PreparePlate {
public:
    void solve(void) {
            vector<int> v(4);
            REP(i, 4)
                cin>>v[i];
            sort(RANGE(v));

            const ll inf = (1<<30);
            // 30*29*28 = 24360 なんで
            // 全探索でいけそう
            ll minN = inf;
            for (int a = 1; a <= 30; ++a)
            for (int b = a+1; b <= 30; ++b)
            for (int c = b+1; c <= 30; ++c)
            {
                vector<ll> dp(30+1, inf);
                dp[0] = 0;
                for (int i = 1; i <= 30; ++i)
                {
                    int x[] = {a,b,c};
                    REP(j, 3) if (i >= x[j])
                        dp[i] = min(dp[i], dp[i-x[j]]+1);
                }
                ll n = 0;
                REP(i,4)
                    n = min(n+dp[v[i]], inf);
                minN = min(n, minN);
            }
            cout<<minN<<endl;
    }
};

#if 1
int main(int argc, char *argv[])
{
        ios::sync_with_stdio(false);
        auto obj = new PreparePlate();
        obj->solve();
        delete obj;
        return 0;
}
#endif