#include <bits/stdc++.h>

using namespace std;
int x,r;
int howManyGames(int p, int d, int m, int s) {
    for(int i=0;i<=s;)
    {//cout<<i<<" ";
        if(p-(x*d)>=m)
        {//cout<<p-(x*d)<<" ";
         i=i+(p-(x*d));}
        else{
            i=i+m;//cout<<m<<" ";
        }
        x++;
        
        
    }
    return x;
}

int main() {
    int p;
    int d;
    int m;
    int s;
    cin >> p >> d >> m >> s;
    int answer = howManyGames(p, d, m, s);
    cout << answer-1 << endl;
    return 0;
}