import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        String[] lines = getStdin();
        String number = lines[0];
        String[] line = number.split(" ");
        int T_hp = Integer.parseInt(line[0]);
        int T_attack = Integer.parseInt(line[1]);
        int A_hp = Integer.parseInt(line[2]);
        int A_attack = Integer.parseInt(line[3]);

        for (int i = 0; i < 100; i++){
            A_hp = A_hp - T_attack;
            if (A_hp <= 0){
                System.out.println("Yes");
                return;
            }
            T_hp = T_hp - A_attack;
            if (T_hp <= 0){
                System.out.println("No");
                return;
            }
        }


    }
  
  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 number = lines[0];
        String[] line = number.split(" ");
        int T_hp = Integer.parseInt(line[0]);
        int T_attack = Integer.parseInt(line[1]);
        int A_hp = Integer.parseInt(line[2]);
        int A_attack = Integer.parseInt(line[3]);

        for (int i = 0; i < 100; i++){
            A_hp = A_hp - T_attack;
            if (A_hp <= 0){
                System.out.println("Yes");
                return;
            }
            T_hp = T_hp - A_attack;
            if (T_hp <= 0){
                System.out.println("No");
                return;
            }
        }


    }
  
  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 number = lines[0];
        String[] line = number.split(" ");
        int T_hp = Integer.parseInt(line[0]);
        int T_attack = Integer.parseInt(line[1]);
        int A_hp = Integer.parseInt(line[2]);
        int A_attack = Integer.parseInt(line[3]);

        for (int i = 0; i < 100; i++){
            A_hp = A_hp - T_attack;
            if (A_hp <= 0){
                System.out.println("Yes");
                return;
            }
            T_hp = T_hp - A_attack;
            if (T_hp <= 0){
                System.out.println("No");
                return;
            }
        }


    } main {
        String[] lines = getStdin();
        String number = lines[0];
        String[] line = number.split(" ");
        int T_hp = Integer.parseInt(line[0]);
        int T_attack = Integer.parseInt(line[1]);
        int A_hp = Integer.parseInt(line[2]);
        int A_attack = Integer.parseInt(line[3]);

        for (int i = 0; i < 100; i++){
            A_hp = A_hp - T_attack;
            if (A_hp <= 0){
                System.out.println("Yes");
                return;
            }
            T_hp = T_hp - A_attack;
            if (T_hp <= 0){
                System.out.println("No");
                return;
            }
        }


    } String[] lines = getStdin(); lines getStdin() getStdin String number = lines[0]; number lines[0] lines 0 String[] line = number.split(" "); line number.split(" ") number.split number " " int T_hp = Integer.parseInt(line[0]); T_hp Integer.parseInt(line[0]) Integer.parseInt Integer line[0] line 0 int T_attack = Integer.parseInt(line[1]); T_attack Integer.parseInt(line[1]) Integer.parseInt Integer line[1] line 1 int A_hp = Integer.parseInt(line[2]); A_hp Integer.parseInt(line[2]) Integer.parseInt Integer line[2] line 2 int A_attack = Integer.parseInt(line[3]); A_attack Integer.parseInt(line[3]) Integer.parseInt Integer line[3] line 3 for (int i = 0; i < 100; i++){
            A_hp = A_hp - T_attack;
            if (A_hp <= 0){
                System.out.println("Yes");
                return;
            }
            T_hp = T_hp - A_attack;
            if (T_hp <= 0){
                System.out.println("No");
                return;
            }
        } int i = 0; int i = 0; i 0 i < 100 i 100 i++ i++ i {
            A_hp = A_hp - T_attack;
            if (A_hp <= 0){
                System.out.println("Yes");
                return;
            }
            T_hp = T_hp - A_attack;
            if (T_hp <= 0){
                System.out.println("No");
                return;
            }
        } {
            A_hp = A_hp - T_attack;
            if (A_hp <= 0){
                System.out.println("Yes");
                return;
            }
            T_hp = T_hp - A_attack;
            if (T_hp <= 0){
                System.out.println("No");
                return;
            }
        } A_hp = A_hp - T_attack A_hp A_hp - T_attack A_hp T_attack if (A_hp <= 0){
                System.out.println("Yes");
                return;
            } A_hp <= 0 A_hp 0 {
                System.out.println("Yes");
                return;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" return; T_hp = T_hp - A_attack T_hp T_hp - A_attack T_hp A_attack if (T_hp <= 0){
                System.out.println("No");
                return;
            } T_hp <= 0 T_hp 0 {
                System.out.println("No");
                return;
            } System.out.println("No") System.out.println System.out System System.out "No" return; 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 number = lines[0];
        String[] line = number.split(" ");
        int T_hp = Integer.parseInt(line[0]);
        int T_attack = Integer.parseInt(line[1]);
        int A_hp = Integer.parseInt(line[2]);
        int A_attack = Integer.parseInt(line[3]);

        for (int i = 0; i < 100; i++){
            A_hp = A_hp - T_attack;
            if (A_hp <= 0){
                System.out.println("Yes");
                return;
            }
            T_hp = T_hp - A_attack;
            if (T_hp <= 0){
                System.out.println("No");
                return;
            }
        }


    }
  
  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 number = lines[0];
        String[] line = number.split(" ");
        int T_hp = Integer.parseInt(line[0]);
        int T_attack = Integer.parseInt(line[1]);
        int A_hp = Integer.parseInt(line[2]);
        int A_attack = Integer.parseInt(line[3]);

        for (int i = 0; i < 100; i++){
            A_hp = A_hp - T_attack;
            if (A_hp <= 0){
                System.out.println("Yes");
                return;
            }
            T_hp = T_hp - A_attack;
            if (T_hp <= 0){
                System.out.println("No");
                return;
            }
        }


    }
  
  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 number = lines[0];
        String[] line = number.split(" ");
        int T_hp = Integer.parseInt(line[0]);
        int T_attack = Integer.parseInt(line[1]);
        int A_hp = Integer.parseInt(line[2]);
        int A_attack = Integer.parseInt(line[3]);

        for (int i = 0; i < 100; i++){
            A_hp = A_hp - T_attack;
            if (A_hp <= 0){
                System.out.println("Yes");
                return;
            }
            T_hp = T_hp - A_attack;
            if (T_hp <= 0){
                System.out.println("No");
                return;
            }
        }


    }
  
  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()]);
  }
  
}
