#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    if(p>s)
        return 0;
    if(p>=m)
        return 1+ howManyGames(p-d,d,m,s-p);
    //cout<<s<<" "<<m<<" "<<s/m<<endl;
    return s/m;
}

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;
}