import java.util.Scanner;

public class Main{
  public static void main(String[] args){
    Scanner scanner = new Scanner(System.in);
    int A = scanner.nextInt();
    int B = scanner.nextInt();
    int C = scanner.nextInt();
    int D = scanner.nextInt();
    
    System.out.println(cal(A,D) >= cal(C,B) ? "Yes" : "No");
  }
  
  private static int cal(int a,int b){
    int i;
    for(i = 0;a - b > 0;i++){
      a = a - b;
    }
    return i;
  }
} import java.util.Scanner; Scanner java.util public class Main{
  public static void main(String[] args){
    Scanner scanner = new Scanner(System.in);
    int A = scanner.nextInt();
    int B = scanner.nextInt();
    int C = scanner.nextInt();
    int D = scanner.nextInt();
    
    System.out.println(cal(A,D) >= cal(C,B) ? "Yes" : "No");
  }
  
  private static int cal(int a,int b){
    int i;
    for(i = 0;a - b > 0;i++){
      a = a - b;
    }
    return i;
  }
} Main public static void main(String[] args){
    Scanner scanner = new Scanner(System.in);
    int A = scanner.nextInt();
    int B = scanner.nextInt();
    int C = scanner.nextInt();
    int D = scanner.nextInt();
    
    System.out.println(cal(A,D) >= cal(C,B) ? "Yes" : "No");
  } main {
    Scanner scanner = new Scanner(System.in);
    int A = scanner.nextInt();
    int B = scanner.nextInt();
    int C = scanner.nextInt();
    int D = scanner.nextInt();
    
    System.out.println(cal(A,D) >= cal(C,B) ? "Yes" : "No");
  } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int A = scanner.nextInt(); A scanner.nextInt() scanner.nextInt scanner int B = scanner.nextInt(); B scanner.nextInt() scanner.nextInt scanner int C = scanner.nextInt(); C scanner.nextInt() scanner.nextInt scanner int D = scanner.nextInt(); D scanner.nextInt() scanner.nextInt scanner System.out.println(cal(A,D) >= cal(C,B) ? "Yes" : "No") System.out.println System.out System System.out cal(A,D) >= cal(C,B) ? "Yes" : "No" cal(A,D) >= cal(C,B) cal(A,D) cal A D cal(C,B) cal C B "Yes" "No" String[] args args private static int cal(int a,int b){
    int i;
    for(i = 0;a - b > 0;i++){
      a = a - b;
    }
    return i;
  } cal {
    int i;
    for(i = 0;a - b > 0;i++){
      a = a - b;
    }
    return i;
  } int i; i for(i = 0;a - b > 0;i++){
      a = a - b;
    } i = 0; i = 0 i 0 a - b > 0 a - b a b 0 i++ i++ i {
      a = a - b;
    } {
      a = a - b;
    } a = a - b a a - b a b return i; i int a a int b b public class Main{
  public static void main(String[] args){
    Scanner scanner = new Scanner(System.in);
    int A = scanner.nextInt();
    int B = scanner.nextInt();
    int C = scanner.nextInt();
    int D = scanner.nextInt();
    
    System.out.println(cal(A,D) >= cal(C,B) ? "Yes" : "No");
  }
  
  private static int cal(int a,int b){
    int i;
    for(i = 0;a - b > 0;i++){
      a = a - b;
    }
    return i;
  }
} public class Main{
  public static void main(String[] args){
    Scanner scanner = new Scanner(System.in);
    int A = scanner.nextInt();
    int B = scanner.nextInt();
    int C = scanner.nextInt();
    int D = scanner.nextInt();
    
    System.out.println(cal(A,D) >= cal(C,B) ? "Yes" : "No");
  }
  
  private static int cal(int a,int b){
    int i;
    for(i = 0;a - b > 0;i++){
      a = a - b;
    }
    return i;
  }
} Main
import java.util.Scanner;

public class Main{
  public static void main(String[] args){
    Scanner scanner = new Scanner(System.in);
    int A = scanner.nextInt();
    int B = scanner.nextInt();
    int C = scanner.nextInt();
    int D = scanner.nextInt();
    
    System.out.println(cal(A,D) >= cal(C,B) ? "Yes" : "No");
  }
  
  private static int cal(int a,int b){
    int i;
    for(i = 0;a - b > 0;i++){
      a = a - b;
    }
    return i;
  }
}