#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 x=0;
    while(true)
    {
        if(s>=p && p>=m)
        {
            s=s-p;
            p=p-d;
            x++;
        }
        else if(s>=m && p<m)
        {
            int t=s/m;
            x=x+t;
            break;
        }
        else 
        {
            break;
        }
    }
    return x;
}

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;
}