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