#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    // Return the number of games you can buy
    long long arr[1000000]={0};
    
    long long x=p,k=0;
   
    while(x>m)
    {
        arr[k++]=x;
        x=x-d;
    }
    arr[k]=m;
  /*  for(int j=0;j<=k;j++)
    {
        cout<<arr[j]<<" ";
    } */
  //  cout<<endl;
    int i=0,ans=0;
    for(long long b=0;b<=k;b++)
    {
        i=i+arr[b];
    }
  //  cout<<i<<endl;
    ans=k+1;
    if(i<=s)
    {
       ans=ans+(s-i)/m;
    }
    
    if(i>s)
    {
        while(i>s)
        {
            ans--;
            i=i-arr[k];
            k--;
        }
        
    }
    
    return ans;
}

int main() {
    int p;
    int d;
    int m;
    int s;
    cin >> p >> d >> m >> s;
    int answer = howManyGames(p, d, m, s);
    cout << answer << endl;
    return 0;
}