#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int p,d,m,s,gc=0;
    cin >> p >> d >> m >> s;
    {
        int i = 0;
        while (true)
        {
            int x = p-(d*i);
            int y = max(x, m);
            if (s < y) break;
            else
            {
                gc++;
                s -= y;
            }
            i++;
        }
        cout << gc << endl;
    }  
    return 0;
}