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

public class Solution {

    static int howManyGames(int price, int discount, int minimun, int money) {
        if (price > money) return 0;
        
        money -= price;
        
        int nextPrice = (price - discount > minimun) ? (price - discount) : minimun;
        
        return 1 + howManyGames(nextPrice, discount, minimun, money);
    }

    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();
    }
}