#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int p,d,m,s,t=0;
    cin>>p>>d>>m>>s;
    while(p>=m&&s>=p)
    {
        s-=p;
        t++;
        p-=d;
    }
    if(p<m)
    {
    while(s-m>=0)
    {
        s-=m;
        t++;
    }
    }
    cout<<t;
    return 0;
}