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[] arr=new int[100];
        int sum=0;
        arr[0]=p;
        int i=1;
        if(p==s){
        System.out.println("1");
    }
        else
        {
            if(p>d&&p>m){
            int count=0;
            while(true){
              p=p-d;
                count++;
                i++;
                for(int j=0;j<arr.length;j++){
                    sum=sum+arr[j];
                }
                if(p==m||sum==s){
                    break;
                }
             } 
               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();
    }
}