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;
        sum+=p;
        int count=1;
        for(int i=1;sum<=s;i++){
            if(p-i*d >=m){
                sum+=p-i*d;
                count++;
            }
            
            else{
                sum+=m;
                count++;
            }
        }
        return count-1;
    }

    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();
    }
}