#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 res = 0;
    int nd = 1;
    int cost = p;
    while ((s -= cost) >= 0) {
        res++;
        if (p - nd*d > m) {
            cost = p-nd*d;
            nd++;
        }
        else 
            cost = m;
    }
    return res;    
}

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;
}