#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 sum = 0;
    int temp = p;
    int count = 0;
    while(sum<=s)
    {
        if(temp<=m)
        {
            temp = m;
            sum = sum + temp;
            //cout<<"sum "<<sum<<endl;
            count++;
        }
        else
        {
            sum = sum + temp;
            //cout<<"sum "<<sum<<endl;
            count++;
            temp = temp - d;
        }
        //cout<<"temp "<<temp<<endl;
        
    }
    count--;
    return count;
    
}

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;
}