
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int attackNumA = (int) Math.ceil((double)A/D);
		//System.out.println(attackNumA);
		int attackNumT = (int) Math.ceil((double)C/B);
		//System.out.println(attackNumT);
		if(attackNumA >= attackNumT) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}
		scan.close();
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int attackNumA = (int) Math.ceil((double)A/D);
		//System.out.println(attackNumA);
		int attackNumT = (int) Math.ceil((double)C/B);
		//System.out.println(attackNumT);
		if(attackNumA >= attackNumT) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}
		scan.close();
	}
} Main public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int attackNumA = (int) Math.ceil((double)A/D);
		//System.out.println(attackNumA);
		int attackNumT = (int) Math.ceil((double)C/B);
		//System.out.println(attackNumT);
		if(attackNumA >= attackNumT) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}
		scan.close();
	} main {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int attackNumA = (int) Math.ceil((double)A/D);
		//System.out.println(attackNumA);
		int attackNumT = (int) Math.ceil((double)C/B);
		//System.out.println(attackNumT);
		if(attackNumA >= attackNumT) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}
		scan.close();
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int A = scan.nextInt(); A scan.nextInt() scan.nextInt scan int B = scan.nextInt(); B scan.nextInt() scan.nextInt scan int C = scan.nextInt(); C scan.nextInt() scan.nextInt scan int D = scan.nextInt(); D scan.nextInt() scan.nextInt scan int attackNumA = (int) Math.ceil((double)A/D); attackNumA (int) Math.ceil((double)A/D) Math.ceil Math (double)A/D (double)A D int attackNumT = (int) Math.ceil((double)C/B); attackNumT (int) Math.ceil((double)C/B) Math.ceil Math (double)C/B (double)C B if(attackNumA >= attackNumT) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		} attackNumA >= attackNumT attackNumA attackNumT {
			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" scan.close() scan.close scan String[] args args public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int attackNumA = (int) Math.ceil((double)A/D);
		//System.out.println(attackNumA);
		int attackNumT = (int) Math.ceil((double)C/B);
		//System.out.println(attackNumT);
		if(attackNumA >= attackNumT) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}
		scan.close();
	}
} public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int attackNumA = (int) Math.ceil((double)A/D);
		//System.out.println(attackNumA);
		int attackNumT = (int) Math.ceil((double)C/B);
		//System.out.println(attackNumT);
		if(attackNumA >= attackNumT) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}
		scan.close();
	}
} Main

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int attackNumA = (int) Math.ceil((double)A/D);
		//System.out.println(attackNumA);
		int attackNumT = (int) Math.ceil((double)C/B);
		//System.out.println(attackNumT);
		if(attackNumA >= attackNumT) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}
		scan.close();
	}
}
