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 counter = 0;
        if(p>s) {
            return 0;
        }
        if(m==p){
            return s/p;
        }
        int cost = p;
        while(s > 0){
            if(s-cost >= 0){
                s-=cost;
                counter++;
            } else {
                break;
            }

            if(cost - d <= m){
                cost = m;
            } else {
                cost-=d;
            }
        }
        return counter;
    }
    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();
    }
}