#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 result = 0 ;
    bool temp = true ; 

    while (s > 0 && p > m)
    {
        if(s - p >= 0)
        {
            result ++ ;
            s = s-p ;
            p = p-d;
        }    
        else
        {
            temp = false ; 
            break ; 
        }
    }

    if(temp == true)
        result += s/m;

    return result;
}

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;
}