import java.util.Scanner;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        float hp = sc.nextInt();
        float at = sc.nextInt();
        float hp2 = sc.nextInt();
        float at2 = sc.nextInt();
        if(Math.ceil(hp/at2) >= Math.ceil(hp2/at)){
            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);
        float hp = sc.nextInt();
        float at = sc.nextInt();
        float hp2 = sc.nextInt();
        float at2 = sc.nextInt();
        if(Math.ceil(hp/at2) >= Math.ceil(hp2/at)){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        float hp = sc.nextInt();
        float at = sc.nextInt();
        float hp2 = sc.nextInt();
        float at2 = sc.nextInt();
        if(Math.ceil(hp/at2) >= Math.ceil(hp2/at)){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    } main {
        Scanner sc = new Scanner(System.in);
        float hp = sc.nextInt();
        float at = sc.nextInt();
        float hp2 = sc.nextInt();
        float at2 = sc.nextInt();
        if(Math.ceil(hp/at2) >= Math.ceil(hp2/at)){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) float hp = sc.nextInt(); hp sc.nextInt() sc.nextInt sc float at = sc.nextInt(); at sc.nextInt() sc.nextInt sc float hp2 = sc.nextInt(); hp2 sc.nextInt() sc.nextInt sc float at2 = sc.nextInt(); at2 sc.nextInt() sc.nextInt sc if(Math.ceil(hp/at2) >= Math.ceil(hp2/at)){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        } Math.ceil(hp/at2) >= Math.ceil(hp2/at) Math.ceil(hp/at2) Math.ceil Math hp/at2 hp at2 Math.ceil(hp2/at) Math.ceil Math hp2/at hp2 at {
            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);
        float hp = sc.nextInt();
        float at = sc.nextInt();
        float hp2 = sc.nextInt();
        float at2 = sc.nextInt();
        if(Math.ceil(hp/at2) >= Math.ceil(hp2/at)){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
} public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        float hp = sc.nextInt();
        float at = sc.nextInt();
        float hp2 = sc.nextInt();
        float at2 = sc.nextInt();
        if(Math.ceil(hp/at2) >= Math.ceil(hp2/at)){
            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);
        float hp = sc.nextInt();
        float at = sc.nextInt();
        float hp2 = sc.nextInt();
        float at2 = sc.nextInt();
        if(Math.ceil(hp/at2) >= Math.ceil(hp2/at)){
            System.out.println("Yes");
        }else{
            System.out.println("No");
        }
    }
}