#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    int i=1,cost=p,count=0;
    if(i==1 && s>=cost)
        {
            s=s-p;
            count++;
            i++;
            
            
        }
    while((cost-d)>m && s>=cost)
    {
        
        
            cost=cost-d;
            s=s-cost;
            count++;
            i++;
        
        
    }
    while(s>=cost)
    {
        cost=m;
        s=s-cost;
        count++;
    }
return count;
    // Return the number of games you can buy
}

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;
}