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();
        if((c+(b-1))/b>(a+(d-1))/d) System.out.println("No");
        else System.out.println("Yes");
    }
} 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();
        if((c+(b-1))/b>(a+(d-1))/d) System.out.println("No");
        else System.out.println("Yes");
    }
} 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();
        if((c+(b-1))/b>(a+(d-1))/d) System.out.println("No");
        else System.out.println("Yes");
    } main {
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        int c = scanner.nextInt();
        int d = scanner.nextInt();
        if((c+(b-1))/b>(a+(d-1))/d) System.out.println("No");
        else System.out.println("Yes");
    } 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 if((c+(b-1))/b>(a+(d-1))/d) System.out.println("No");
        else System.out.println("Yes"); (c+(b-1))/b>(a+(d-1))/d (c+(b-1))/b (c+(b-1)) c (b-1) b 1 b (a+(d-1))/d (a+(d-1)) a (d-1) d 1 d System.out.println("No") System.out.println System.out System System.out "No" System.out.println("Yes") System.out.println System.out System System.out "Yes" String[] args args 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();
        if((c+(b-1))/b>(a+(d-1))/d) System.out.println("No");
        else System.out.println("Yes");
    }
} 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();
        if((c+(b-1))/b>(a+(d-1))/d) System.out.println("No");
        else System.out.println("Yes");
    }
} 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();
        if((c+(b-1))/b>(a+(d-1))/d) System.out.println("No");
        else System.out.println("Yes");
    }
}
