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

public class Solution {

    
    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();
    }
    static int howManyGames(int p,int d,int m,int s){
        int total=0;
        int v=p;
        int n=0;
        while (total<=s){
            v=p-n*d;
            n+=1;
            if(v<m){
                v=m;
            }
            total+=v;
                
        }
        return n-1;
    }
}