#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) 
{
    int final_ans = 0;
    int curr_cost = p;
    
    while(s > 0)
    {
        if(curr_cost <= s)      
            final_ans++;
        
        s -= curr_cost;
        
        if(curr_cost-d >= m)
            curr_cost -= d;       
        else
            curr_cost = m;
    }
    
    return final_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;
}