#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    int total = 0;
    int price = p;
    if(p <= s){
        total++;
        s -= p; 
        price -= d;
    }
    while(s >= price){
        if(price >= m){
            total++;
            s -= price;
            price -=d;
        }
        else{
            price = m;
            if(s >= m){
            total++;
            s -= price;
            }
        }
    }
    return total;
}

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;
}