#include <bits/stdc++.h>

using namespace std;


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