content: import java.io.*;
  import java.math.*;
  import java.security.*;
  import java.text.*;
  import java.util.*;
  import java.util.concurrent.*;
  import java.util.regex.*;
  
  public class Solution {
  
    // Complete the howManyGames function below.
    static int howManyGames(int p, int d, int m, int s) {
      int counter = 0;
      int current = p;
      while (s >= current) {
        counter++;
        s -= current;
        if (current - d < m) {
          current = m;
        } else {
          current -= d;
        }
      }
  
      return counter;
    }
  
    private static final Scanner scanner = new Scanner(System.in);
  
    public static void main(String[] args) throws IOException {
      BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));
  
      String[] pdms = scanner.nextLine().split(" ");
  
      int p = Integer.parseInt(pdms[0]);
  
      int d = Integer.parseInt(pdms[1]);
  
      int m = Integer.parseInt(pdms[2]);
  
      int s = Integer.parseInt(pdms[3]);
  
      int answer = howManyGames(p, d, m, s);
  
      bufferedWriter.write(String.valueOf(answer));
      bufferedWriter.newLine();
  
      bufferedWriter.close();
  
      scanner.close();
    }
  }
  