#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s)
{
    int sum=0,i=2;
     while(sum<s)
     {
         if(p>=m)
         {
          sum=(sum)+(p);
         i++;
         p-3;
         }
     }
       
    return i;
    
}

int main() {
    int p;
    int d;
    int m;
    int s;
    cin >> p >> d >> m >> s;
    int answer = howManyGames(p, d, m, s);
    cout << answer << endl;
    return 0;
}