#include <bits/stdc++.h>

using namespace std;

int main() 
{
    int p;
    int d;
    int m;
    int s;
    int i,sum1=0,c1=0,sum2,c2=0,j;
    cin >> p >> d >> m >> s;
    for(i=p;i>m;i=i-d)
    {
        while(sum1<=s )
        {
            sum1=sum1+i;
            c1++;
        }
    }
    for(j=0;j<10;j++)
    {
        while(sum2<=s)
        {
                sum2=sum1+m;
                c2++;
        }
    }
          
    
    cout<<c1+c2;
    
}