#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 count=0;
    while(true){
        if(p>m){
            if(s>=p){
                s-=p;
                count++;
                p-=d;
            }
        }
        else if(p<=m){
            if(s>=m){
                s-=m;
                count++;
            }
        }
        if(s<p && p>m)
            break;
        if(s<m || s<=0){
            break;
        }
    }
    return count;
}

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;
}