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) {
      int t=p , sum=p, c=1 ;
      sum-=d;
      if(s<p) return 0;
      while(sum <= s && s-sum >=d)
      {
        if((t - d) > m )
        { t-=d; sum+=t; c++;}
        else 
        { c++; sum+=m;}  
      }
      return c-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();
    }
}