#include <bits/stdc++.h>

using namespace std;

int howManyGames(int p, int d, int m, int s) {
    int no_of_games=0,t_cost=0,cost;
    while(1)
    { 
        
        cost = p-d*no_of_games;
      
        if(cost<m)
            cost =m;
        t_cost = t_cost+cost;
        if(t_cost>s)
            break;
          no_of_games++;
        
        
        
    }
    return (no_of_games);
    // 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;
}