#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 numGames = 0;   // Number of games
    bool done = false;  // Check unable to afford more
    int cost = 0;       // Cost of games
    int subtotal;       // Subtotal calculated
    int i = 0;          // Temporary number of games
    
    while(s > cost && !done){
        
        subtotal = cost;
        
        // 
        if(p-i*d > m)
            subtotal += p-i*d;
        else
            subtotal += m;
        
        // Check that subtotal doesn't exceed dollars available
        if(s-subtotal >= 0){
    
            cost = subtotal;
            numGames++;
        }
        else
            done = true;
        
        i++;
    }
    
    return numGames;
}

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;
}