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 sum=0;
        int count=0;
        while(sum <= s)
        {
            if(p>=m)
            {
            sum+=p;
                count++;
                 //System.out.println("sum "+sum);
            }
            
            if(p-d>m)
            {
            p-=d;
                // System.out.println("p " +p);
            
            }
            else
            {
                p=m;
      
            }
           
          
        }
        count--;
        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();
    }
}