import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static int howManyGames(int p, int d, int m, int s) {
        // Return the number of games you can buy
        int total_money=0;
        int cost=0;
        int i=0;
        for(;i<10000;i++){
            cost=p-(i*d);
            if(cost<=m){
               cost=m;
            }
            total_money+=cost;
            //System.out.println(cost);
            if(total_money>s){
               break;
            }   
            //System.out.println(total_money);
            
            
        }
        return i;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int p = in.nextInt();
        int d = in.nextInt();
        int m = in.nextInt();
        int s = in.nextInt();
        int answer = howManyGames(p, d, m, s);
        System.out.println(answer);
        in.close();
    }
}