#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
    int cnt=0;int z=0,I=0;
    for(int i=0;;i++)
    { cnt++;
        if(!i){
        s-=p;  if(s<0){return I;}
             }else{
        if(p-d>m){p-=d; s-=p;I=i; if(s<0)return I; }
         else if(p-d<=m){s-=m; I=i; if(s<0)return I;}
        /*
        cout<<p-d<<" ";
       
            if(cnt==10)return 0;
    */
    }
    }
  //  if(!I)return I+1; else return 0;
}

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;
}