#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 cnt = 0;
    while(s > 0){
        if(p - cnt * d <= m){
            if(s < m)break;
            s -= m;
            //cout << m << endl;
        }
        else {
            if(s < p - cnt * d)break;
            s -= p - cnt * d;
            //cout << p - cnt * d << endl;
        }
        cnt++;
        //cout << s << " " << p << endl;
    }
    return cnt;
}

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;
}