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 cnt = 0;
        for(int i=0; ; i++){
            if (i == 0){
            sum = sum + p;
            if (s >= sum)
                cnt++;
                else
                    break;
            }
            else{
                if (p - d*i >= m){
                sum = sum + p - d*i;
                if (s >= sum)
                    cnt++;
                    else
                        break;
                }
                else{
                    sum = sum + m;
                    if (s >= sum)
                        cnt++;
                    else
                        break;
                }
                
            }
        }
        return cnt;
    }

    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();
    }
}