import java.util.Scanner;

public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();    
    double ad = (double)a / d;
    double cd = (double)c / b;
    int ansa = 0;
    int ansc = 0;
    if(ad % 1 != 0){
      ad++;
      ansa = (int)ad;
    }else{
      ansa = (int)ad;
    }
    
    if(cd % 1 != 0){
      cd++;
       ansc = (int)cd;
    }else{
      ansc = (int)cd;
    }  
    if(ansa >= ansc){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  }
} import java.util.Scanner; Scanner java.util public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();    
    double ad = (double)a / d;
    double cd = (double)c / b;
    int ansa = 0;
    int ansc = 0;
    if(ad % 1 != 0){
      ad++;
      ansa = (int)ad;
    }else{
      ansa = (int)ad;
    }
    
    if(cd % 1 != 0){
      cd++;
       ansc = (int)cd;
    }else{
      ansc = (int)cd;
    }  
    if(ansa >= ansc){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  }
} Main public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();    
    double ad = (double)a / d;
    double cd = (double)c / b;
    int ansa = 0;
    int ansc = 0;
    if(ad % 1 != 0){
      ad++;
      ansa = (int)ad;
    }else{
      ansa = (int)ad;
    }
    
    if(cd % 1 != 0){
      cd++;
       ansc = (int)cd;
    }else{
      ansc = (int)cd;
    }  
    if(ansa >= ansc){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  } main {
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();    
    double ad = (double)a / d;
    double cd = (double)c / b;
    int ansa = 0;
    int ansc = 0;
    if(ad % 1 != 0){
      ad++;
      ansa = (int)ad;
    }else{
      ansa = (int)ad;
    }
    
    if(cd % 1 != 0){
      cd++;
       ansc = (int)cd;
    }else{
      ansc = (int)cd;
    }  
    if(ansa >= ansc){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = sc.nextInt(); b sc.nextInt() sc.nextInt sc int c = sc.nextInt(); c sc.nextInt() sc.nextInt sc int d = sc.nextInt(); d sc.nextInt() sc.nextInt sc double ad = (double)a / d; ad (double)a / d (double)a d double cd = (double)c / b; cd (double)c / b (double)c b int ansa = 0; ansa 0 int ansc = 0; ansc 0 if(ad % 1 != 0){
      ad++;
      ansa = (int)ad;
    }else{
      ansa = (int)ad;
    } ad % 1 != 0 ad % 1 ad 1 0 {
      ad++;
      ansa = (int)ad;
    } ad++ ad ansa = (int)ad ansa (int)ad {
      ansa = (int)ad;
    } ansa = (int)ad ansa (int)ad if(cd % 1 != 0){
      cd++;
       ansc = (int)cd;
    }else{
      ansc = (int)cd;
    } cd % 1 != 0 cd % 1 cd 1 0 {
      cd++;
       ansc = (int)cd;
    } cd++ cd ansc = (int)cd ansc (int)cd {
      ansc = (int)cd;
    } ansc = (int)cd ansc (int)cd if(ansa >= ansc){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    } ansa >= ansc ansa ansc {
      System.out.println("Yes");
    } System.out.println("Yes") System.out.println System.out System System.out "Yes" {
      System.out.println("No");
    } System.out.println("No") System.out.println System.out System System.out "No" String args[] args public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();    
    double ad = (double)a / d;
    double cd = (double)c / b;
    int ansa = 0;
    int ansc = 0;
    if(ad % 1 != 0){
      ad++;
      ansa = (int)ad;
    }else{
      ansa = (int)ad;
    }
    
    if(cd % 1 != 0){
      cd++;
       ansc = (int)cd;
    }else{
      ansc = (int)cd;
    }  
    if(ansa >= ansc){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  }
} public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();    
    double ad = (double)a / d;
    double cd = (double)c / b;
    int ansa = 0;
    int ansc = 0;
    if(ad % 1 != 0){
      ad++;
      ansa = (int)ad;
    }else{
      ansa = (int)ad;
    }
    
    if(cd % 1 != 0){
      cd++;
       ansc = (int)cd;
    }else{
      ansc = (int)cd;
    }  
    if(ansa >= ansc){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  }
} Main
import java.util.Scanner;

public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int b = sc.nextInt();
    int c = sc.nextInt();
    int d = sc.nextInt();    
    double ad = (double)a / d;
    double cd = (double)c / b;
    int ansa = 0;
    int ansc = 0;
    if(ad % 1 != 0){
      ad++;
      ansa = (int)ad;
    }else{
      ansa = (int)ad;
    }
    
    if(cd % 1 != 0){
      cd++;
       ansc = (int)cd;
    }else{
      ansc = (int)cd;
    }  
    if(ansa >= ansc){
      System.out.println("Yes");
    }else{
      System.out.println("No");
    }
  }
}