#include <bits/stdc++.h>

using namespace std;

int main() {
    int p;
    int d;
    int m;
    int s;
    cin >> p >> d >> m >> s;
    long long int answer=0;
    while(s>=p)
    {
        s=s-p;
        answer++;
        if(p>=m+d)
        p=p-d;
        else
            p=m;   
    }
    cout << answer << endl;
    return 0;
}