#include<bits/stdc++.h>
using namespace std;

int main()
{
    int p, d, m, s;

    cin >> p >> d >> m >> s;

    int count=0;

    while(s>=m){
        if (p<=m){
            s-=m;
            if (s<0) break;
            count++;
        }
        else{
            s-=p;
            if (s<0) break;
            p-=d;
            count++;
        }
    }
    cout << count << endl;
    return 0;
}