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();

		int A_mod = A / D;
		if (A % D > 0) {
			A_mod++;
		}

		int B_mod = C / B;
		if (C % B > 0) {
			B_mod++;
		}

		if (A_mod >= B_mod) {
			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();

		int A_mod = A / D;
		if (A % D > 0) {
			A_mod++;
		}

		int B_mod = C / B;
		if (C % B > 0) {
			B_mod++;
		}

		if (A_mod >= B_mod) {
			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();

		int A_mod = A / D;
		if (A % D > 0) {
			A_mod++;
		}

		int B_mod = C / B;
		if (C % B > 0) {
			B_mod++;
		}

		if (A_mod >= B_mod) {
			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();

		int A_mod = A / D;
		if (A % D > 0) {
			A_mod++;
		}

		int B_mod = C / B;
		if (C % B > 0) {
			B_mod++;
		}

		if (A_mod >= B_mod) {
			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 int A_mod = A / D; A_mod A / D A D if (A % D > 0) {
			A_mod++;
		} A % D > 0 A % D A D 0 {
			A_mod++;
		} A_mod++ A_mod int B_mod = C / B; B_mod C / B C B if (C % B > 0) {
			B_mod++;
		} C % B > 0 C % B C B 0 {
			B_mod++;
		} B_mod++ B_mod if (A_mod >= B_mod) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		} A_mod >= B_mod A_mod B_mod {
			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();

		int A_mod = A / D;
		if (A % D > 0) {
			A_mod++;
		}

		int B_mod = C / B;
		if (C % B > 0) {
			B_mod++;
		}

		if (A_mod >= B_mod) {
			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();

		int A_mod = A / D;
		if (A % D > 0) {
			A_mod++;
		}

		int B_mod = C / B;
		if (C % B > 0) {
			B_mod++;
		}

		if (A_mod >= B_mod) {
			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();

		int A_mod = A / D;
		if (A % D > 0) {
			A_mod++;
		}

		int B_mod = C / B;
		if (C % B > 0) {
			B_mod++;
		}

		if (A_mod >= B_mod) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}

	}
}