#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 i=0,count=0;
    while(s>=0){
        //cout<<s<<endl;
        if(p-i*d>m){
            s-=(p-i*d);
        i++;
        }else{
            s-=m;
        }
        if(s<0){
            break;
        }
        count++;
    }
    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;
}