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 rem =s;
        int cur = p;
        boolean flag = true;
        while(rem >= cur ){
            count++;
            //System.out.println(cur);
            rem = rem - cur;
            
            if(cur > m && flag){
                if((cur -d)>m)
                    cur = cur -d;
                else{
                        cur = m;
                        flag = false;
                    }
            }
        }
        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();
    }
}