import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scanner = new Scanner(System.in);

		//入力表示
		int A = scanner.nextInt();
		int B = scanner.nextInt();
		int C = scanner.nextInt();
		int D = scanner.nextInt();

		int X = (A + D - 1) / D;
		int Y = (C + B - 1) / B;

		String ans= X >= Y ? "Yes" : "No";
		System.out.println(ans);
	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scanner = new Scanner(System.in);

		//入力表示
		int A = scanner.nextInt();
		int B = scanner.nextInt();
		int C = scanner.nextInt();
		int D = scanner.nextInt();

		int X = (A + D - 1) / D;
		int Y = (C + B - 1) / B;

		String ans= X >= Y ? "Yes" : "No";
		System.out.println(ans);
	}

} Main public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scanner = new Scanner(System.in);

		//入力表示
		int A = scanner.nextInt();
		int B = scanner.nextInt();
		int C = scanner.nextInt();
		int D = scanner.nextInt();

		int X = (A + D - 1) / D;
		int Y = (C + B - 1) / B;

		String ans= X >= Y ? "Yes" : "No";
		System.out.println(ans);
	} main {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scanner = new Scanner(System.in);

		//入力表示
		int A = scanner.nextInt();
		int B = scanner.nextInt();
		int C = scanner.nextInt();
		int D = scanner.nextInt();

		int X = (A + D - 1) / D;
		int Y = (C + B - 1) / B;

		String ans= X >= Y ? "Yes" : "No";
		System.out.println(ans);
	} 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 int X = (A + D - 1) / D; X (A + D - 1) / D (A + D - 1) A + D A D 1 D int Y = (C + B - 1) / B; Y (C + B - 1) / B (C + B - 1) C + B C B 1 B String ans= X >= Y ? "Yes" : "No"; ans X >= Y ? "Yes" : "No" X >= Y X Y "Yes" "No" System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scanner = new Scanner(System.in);

		//入力表示
		int A = scanner.nextInt();
		int B = scanner.nextInt();
		int C = scanner.nextInt();
		int D = scanner.nextInt();

		int X = (A + D - 1) / D;
		int Y = (C + B - 1) / B;

		String ans= X >= Y ? "Yes" : "No";
		System.out.println(ans);
	}

} public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scanner = new Scanner(System.in);

		//入力表示
		int A = scanner.nextInt();
		int B = scanner.nextInt();
		int C = scanner.nextInt();
		int D = scanner.nextInt();

		int X = (A + D - 1) / D;
		int Y = (C + B - 1) / B;

		String ans= X >= Y ? "Yes" : "No";
		System.out.println(ans);
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scanner = new Scanner(System.in);

		//入力表示
		int A = scanner.nextInt();
		int B = scanner.nextInt();
		int C = scanner.nextInt();
		int D = scanner.nextInt();

		int X = (A + D - 1) / D;
		int Y = (C + B - 1) / B;

		String ans= X >= Y ? "Yes" : "No";
		System.out.println(ans);
	}

}
