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 toy = 0;
        int price = p;
        for(int i=0;price<=s;i++){
            {
                toy++;
                if(p-d>m){
                    price+=p-d;
                    p = p - d;
                }
                else{
                    price+=m;
                }
            }
        }
        return toy;
    }

    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();
    }
}