#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,price,sum=0,n=0 ;
    cin >> p >> d >> m >> s ;
    while(s>=0)
    {
       if(n==0)
       { 
           price = p ;
           s -= price ; 
           n++ ; 
       }
       else
       {
          price -= d ;
          if(price >= m)
          {
            s -= price ;
            n++ ;  
          }
          else
          {
            s -= m ;
            n++ ;  
          }    
       }    
    }    
    cout << n-1 ;
    
    
    return 0;
}