#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 total=0;
    int c=0;
    
    while((total<=s)&&(p>m)){
        c++;
        total=total+p;
        p=p-d;
        }
     while(total<=s){
          c++;
         total=total+m;
        
     }
    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;
}