#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    int buy=0;
    int i=0;
    int only = 0;
    while(p>=m)
    {
        if(i=0)
        {
            s=s-p;
            ++buy;
            ++i;
        }
        if((p-d)<m && only == 0)
        {
        p = d;
        p = p-d;
        s=s-p;
        ++buy;
        ++i;
        only++;
        }
        else
        {
        p = p-d;
        s=s-p;
        ++buy;
        ++i;
        }
    }
    while(s>=0)
    {
        s=s-p;
        ++buy;
    }
    return buy;
}

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;
}