import java.util.*;
public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String[] str = lines[0].split(" ");
        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);
        
           while(a > 0 && c > 0){
               c = c - b;
                if (c <= 0){
                    System.out.println("Yes");
                    break;
                }
               a = a - d;
                if (a <= 0){
                    System.out.println("No");
                    break;
                }
           } 
               
   }
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String[] str = lines[0].split(" ");
        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);
        
           while(a > 0 && c > 0){
               c = c - b;
                if (c <= 0){
                    System.out.println("Yes");
                    break;
                }
               a = a - d;
                if (a <= 0){
                    System.out.println("No");
                    break;
                }
           } 
               
   }
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
} Main public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String[] str = lines[0].split(" ");
        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);
        
           while(a > 0 && c > 0){
               c = c - b;
                if (c <= 0){
                    System.out.println("Yes");
                    break;
                }
               a = a - d;
                if (a <= 0){
                    System.out.println("No");
                    break;
                }
           } 
               
   } main {
        String[] lines = getStdin();
        String[] str = lines[0].split(" ");
        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);
        
           while(a > 0 && c > 0){
               c = c - b;
                if (c <= 0){
                    System.out.println("Yes");
                    break;
                }
               a = a - d;
                if (a <= 0){
                    System.out.println("No");
                    break;
                }
           } 
               
   } String[] lines = getStdin(); lines getStdin() getStdin String[] str = lines[0].split(" "); str lines[0].split(" ") lines[0].split lines[0] lines 0 " " int a = Integer.parseInt(str[0]); a Integer.parseInt(str[0]) Integer.parseInt Integer str[0] str 0 int b = Integer.parseInt(str[1]); b Integer.parseInt(str[1]) Integer.parseInt Integer str[1] str 1 int c = Integer.parseInt(str[2]); c Integer.parseInt(str[2]) Integer.parseInt Integer str[2] str 2 int d = Integer.parseInt(str[3]); d Integer.parseInt(str[3]) Integer.parseInt Integer str[3] str 3 while(a > 0 && c > 0){
               c = c - b;
                if (c <= 0){
                    System.out.println("Yes");
                    break;
                }
               a = a - d;
                if (a <= 0){
                    System.out.println("No");
                    break;
                }
           } a > 0 && c > 0 a > 0 a 0 c > 0 c 0 {
               c = c - b;
                if (c <= 0){
                    System.out.println("Yes");
                    break;
                }
               a = a - d;
                if (a <= 0){
                    System.out.println("No");
                    break;
                }
           } c = c - b c c - b c b if (c <= 0){
                    System.out.println("Yes");
                    break;
                } c <= 0 c 0 {
                    System.out.println("Yes");
                    break;
                } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; a = a - d a a - d a d if (a <= 0){
                    System.out.println("No");
                    break;
                } a <= 0 a 0 {
                    System.out.println("No");
                    break;
                } System.out.println("No") System.out.println System.out System System.out "No" break; String[] args args private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  } getStdin {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) ArrayList<String> lines = new ArrayList<>(); lines new ArrayList<>() while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    } scanner.hasNext() scanner.hasNext scanner {
      lines.add(scanner.nextLine());
    } lines.add(scanner.nextLine()) lines.add lines scanner.nextLine() scanner.nextLine scanner return lines.toArray(new String[lines.size()]); lines.toArray(new String[lines.size()]) lines.toArray lines new String[lines.size()] lines.size() lines.size lines public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String[] str = lines[0].split(" ");
        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);
        
           while(a > 0 && c > 0){
               c = c - b;
                if (c <= 0){
                    System.out.println("Yes");
                    break;
                }
               a = a - d;
                if (a <= 0){
                    System.out.println("No");
                    break;
                }
           } 
               
   }
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
} public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String[] str = lines[0].split(" ");
        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);
        
           while(a > 0 && c > 0){
               c = c - b;
                if (c <= 0){
                    System.out.println("Yes");
                    break;
                }
               a = a - d;
                if (a <= 0){
                    System.out.println("No");
                    break;
                }
           } 
               
   }
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
} Main
import java.util.*;
public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String[] str = lines[0].split(" ");
        int a = Integer.parseInt(str[0]);
        int b = Integer.parseInt(str[1]);
        int c = Integer.parseInt(str[2]);
        int d = Integer.parseInt(str[3]);
        
           while(a > 0 && c > 0){
               c = c - b;
                if (c <= 0){
                    System.out.println("Yes");
                    break;
                }
               a = a - d;
                if (a <= 0){
                    System.out.println("No");
                    break;
                }
           } 
               
   }
  private static String[] getStdin() {
    Scanner scanner = new Scanner(System.in);
    ArrayList<String> lines = new ArrayList<>();
    while (scanner.hasNext()) {
      lines.add(scanner.nextLine());
    }
    return lines.toArray(new String[lines.size()]);
  }
}