#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 q,c=0;
    while(q<=s){
        if(p>m){
            q=q+p;
            c=c+1;
            p=p-d;
        }
        else{
            q=q+m;
            c=c+1;
        }
    }
    return c-1;
}

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;
}