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) {
        int count=0;
        int i=0;
        int cost=p;
        boolean is=false;
        
        while(s>=0){
            cost= p- i*d;
            if(cost>m){
                s=s-cost; 
                i++;
            }else if(cost<=m || is==true ){
                is=true;
                cost= m;
                s=s-cost;
            }
            count++;
        }
        return count-1;
    }

    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();
    }
}