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


int main() {
  int p,d,m,i,s,c=0;
    cin>>p>>d>>m>>s;
    for(i=0;i<100000;i++)
    {if(p>m)
    {s=s-p;
      c++;  
    }
     else
     {s=s-m;
      c++;
     }
     p-=d;
     if(s<0)
     {c--;
      break;
         
     }
    }
    cout<<c<<"\n";
    return 0;
}