#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    // Return the number of games you can buy
        int count =0;
        bool f = true;
        for(int i=p;i>=m;i=i-d)
        {
                if(s<i)
                { f = false;
                        break;
                }
                else
                {
                        s=s-i;
                        count++;
                      //  cout<<s<<" "<<i<<endl;
                }
        }
        if(f)
        {
                while(s>=m)
                {
                        count++;
                        s=s-m;
                }
        }
       // cout<<s<<endl;
        return count;
}

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;
}