#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 count = 0;
    
    while(s > 0)
    {
        s -= p;   
        
        if (p != m && (p - d) > m)
            p -= d;
        else
            p = m;
    
        if (s >= 0)
            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;
}