import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double A = sc.nextDouble();
		double B = sc.nextDouble();
		double C = sc.nextDouble();
		double D = sc.nextDouble();
		System.out.println(Math.ceil(A/D)>=Math.ceil(C/B)?"Yes":"No");
	}

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

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double A = sc.nextDouble();
		double B = sc.nextDouble();
		double C = sc.nextDouble();
		double D = sc.nextDouble();
		System.out.println(Math.ceil(A/D)>=Math.ceil(C/B)?"Yes":"No");
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double A = sc.nextDouble();
		double B = sc.nextDouble();
		double C = sc.nextDouble();
		double D = sc.nextDouble();
		System.out.println(Math.ceil(A/D)>=Math.ceil(C/B)?"Yes":"No");
	} main {
		Scanner sc = new Scanner(System.in);
		double A = sc.nextDouble();
		double B = sc.nextDouble();
		double C = sc.nextDouble();
		double D = sc.nextDouble();
		System.out.println(Math.ceil(A/D)>=Math.ceil(C/B)?"Yes":"No");
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) double A = sc.nextDouble(); A sc.nextDouble() sc.nextDouble sc double B = sc.nextDouble(); B sc.nextDouble() sc.nextDouble sc double C = sc.nextDouble(); C sc.nextDouble() sc.nextDouble sc double D = sc.nextDouble(); D sc.nextDouble() sc.nextDouble sc System.out.println(Math.ceil(A/D)>=Math.ceil(C/B)?"Yes":"No") System.out.println System.out System System.out Math.ceil(A/D)>=Math.ceil(C/B)?"Yes":"No" Math.ceil(A/D)>=Math.ceil(C/B) Math.ceil(A/D) Math.ceil Math A/D A D Math.ceil(C/B) Math.ceil Math C/B C B "Yes" "No" String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double A = sc.nextDouble();
		double B = sc.nextDouble();
		double C = sc.nextDouble();
		double D = sc.nextDouble();
		System.out.println(Math.ceil(A/D)>=Math.ceil(C/B)?"Yes":"No");
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double A = sc.nextDouble();
		double B = sc.nextDouble();
		double C = sc.nextDouble();
		double D = sc.nextDouble();
		System.out.println(Math.ceil(A/D)>=Math.ceil(C/B)?"Yes":"No");
	}

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

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double A = sc.nextDouble();
		double B = sc.nextDouble();
		double C = sc.nextDouble();
		double D = sc.nextDouble();
		System.out.println(Math.ceil(A/D)>=Math.ceil(C/B)?"Yes":"No");
	}

}
