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) {
        // Return the number of games you can buy
        int count = 0;
        int flag = 1;
        while(flag == 1){
            if(s>=p){
                s = s-p;
                count++;
                if((p-d)>=m){
                    p = p-d;
                }
                else{
                    p = m;
                }
            }
            else{
                flag = 0;
            }
        }
        if(s<0){
            count = count - 1;
        }
        return count;
    }

    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();
    }
}