import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		int takaHP = sc.nextInt();
        int takaA = sc.nextInt();
		int aokiHP = sc.nextInt();
        int aokiA = sc.nextInt();
      
      while(takaHP>0){
        aokiHP -= takaA;
        if(aokiHP<=0){
          break;
        }
        takaHP -= aokiA;
      }
      
      if(aokiHP<=0){
      System.out.println("Yes");
      }else{
      System.out.println("No");
      }
    }
} import java.util.*; util.* java public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		int takaHP = sc.nextInt();
        int takaA = sc.nextInt();
		int aokiHP = sc.nextInt();
        int aokiA = sc.nextInt();
      
      while(takaHP>0){
        aokiHP -= takaA;
        if(aokiHP<=0){
          break;
        }
        takaHP -= aokiA;
      }
      
      if(aokiHP<=0){
      System.out.println("Yes");
      }else{
      System.out.println("No");
      }
    }
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		int takaHP = sc.nextInt();
        int takaA = sc.nextInt();
		int aokiHP = sc.nextInt();
        int aokiA = sc.nextInt();
      
      while(takaHP>0){
        aokiHP -= takaA;
        if(aokiHP<=0){
          break;
        }
        takaHP -= aokiA;
      }
      
      if(aokiHP<=0){
      System.out.println("Yes");
      }else{
      System.out.println("No");
      }
    } main {
		Scanner sc = new Scanner(System.in);

		int takaHP = sc.nextInt();
        int takaA = sc.nextInt();
		int aokiHP = sc.nextInt();
        int aokiA = sc.nextInt();
      
      while(takaHP>0){
        aokiHP -= takaA;
        if(aokiHP<=0){
          break;
        }
        takaHP -= aokiA;
      }
      
      if(aokiHP<=0){
      System.out.println("Yes");
      }else{
      System.out.println("No");
      }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int takaHP = sc.nextInt(); takaHP sc.nextInt() sc.nextInt sc int takaA = sc.nextInt(); takaA sc.nextInt() sc.nextInt sc int aokiHP = sc.nextInt(); aokiHP sc.nextInt() sc.nextInt sc int aokiA = sc.nextInt(); aokiA sc.nextInt() sc.nextInt sc while(takaHP>0){
        aokiHP -= takaA;
        if(aokiHP<=0){
          break;
        }
        takaHP -= aokiA;
      } takaHP>0 takaHP 0 {
        aokiHP -= takaA;
        if(aokiHP<=0){
          break;
        }
        takaHP -= aokiA;
      } aokiHP -= takaA aokiHP takaA if(aokiHP<=0){
          break;
        } aokiHP<=0 aokiHP 0 {
          break;
        } break; takaHP -= aokiA takaHP aokiA if(aokiHP<=0){
      System.out.println("Yes");
      }else{
      System.out.println("No");
      } aokiHP<=0 aokiHP 0 {
      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 takaHP = sc.nextInt();
        int takaA = sc.nextInt();
		int aokiHP = sc.nextInt();
        int aokiA = sc.nextInt();
      
      while(takaHP>0){
        aokiHP -= takaA;
        if(aokiHP<=0){
          break;
        }
        takaHP -= aokiA;
      }
      
      if(aokiHP<=0){
      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 takaHP = sc.nextInt();
        int takaA = sc.nextInt();
		int aokiHP = sc.nextInt();
        int aokiA = sc.nextInt();
      
      while(takaHP>0){
        aokiHP -= takaA;
        if(aokiHP<=0){
          break;
        }
        takaHP -= aokiA;
      }
      
      if(aokiHP<=0){
      System.out.println("Yes");
      }else{
      System.out.println("No");
      }
    }
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		int takaHP = sc.nextInt();
        int takaA = sc.nextInt();
		int aokiHP = sc.nextInt();
        int aokiA = sc.nextInt();
      
      while(takaHP>0){
        aokiHP -= takaA;
        if(aokiHP<=0){
          break;
        }
        takaHP -= aokiA;
      }
      
      if(aokiHP<=0){
      System.out.println("Yes");
      }else{
      System.out.println("No");
      }
    }
}
