import java.util.ArrayList;
import java.util.Scanner;

public class Main {
	

	
	public static void main(String[] args) {

		
		Scanner s = new Scanner(System.in);
		
			int a = s.nextInt();
			int b = s.nextInt();
			int c = s.nextInt();
			int d = s.nextInt();
			
			int ans1=0,ans2=0;
			if(a%d==0) {
				ans1=a/d;
			}
			else {
				ans1=a/d+1;
			}
			if(c%b==0) {
				ans2 = c/b;
			}
			else {
				ans2 = c/b+1;
			}
			if(ans1>=ans2) {
				System.out.println("Yes");
			}
			else {
				System.out.println("No");
			}
			

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

	
	public static void main(String[] args) {

		
		Scanner s = new Scanner(System.in);
		
			int a = s.nextInt();
			int b = s.nextInt();
			int c = s.nextInt();
			int d = s.nextInt();
			
			int ans1=0,ans2=0;
			if(a%d==0) {
				ans1=a/d;
			}
			else {
				ans1=a/d+1;
			}
			if(c%b==0) {
				ans2 = c/b;
			}
			else {
				ans2 = c/b+1;
			}
			if(ans1>=ans2) {
				System.out.println("Yes");
			}
			else {
				System.out.println("No");
			}
			

		
		
	}
} Main public static void main(String[] args) {

		
		Scanner s = new Scanner(System.in);
		
			int a = s.nextInt();
			int b = s.nextInt();
			int c = s.nextInt();
			int d = s.nextInt();
			
			int ans1=0,ans2=0;
			if(a%d==0) {
				ans1=a/d;
			}
			else {
				ans1=a/d+1;
			}
			if(c%b==0) {
				ans2 = c/b;
			}
			else {
				ans2 = c/b+1;
			}
			if(ans1>=ans2) {
				System.out.println("Yes");
			}
			else {
				System.out.println("No");
			}
			

		
		
	} main {

		
		Scanner s = new Scanner(System.in);
		
			int a = s.nextInt();
			int b = s.nextInt();
			int c = s.nextInt();
			int d = s.nextInt();
			
			int ans1=0,ans2=0;
			if(a%d==0) {
				ans1=a/d;
			}
			else {
				ans1=a/d+1;
			}
			if(c%b==0) {
				ans2 = c/b;
			}
			else {
				ans2 = c/b+1;
			}
			if(ans1>=ans2) {
				System.out.println("Yes");
			}
			else {
				System.out.println("No");
			}
			

		
		
	} Scanner s = new Scanner(System.in); s new Scanner(System.in) int a = s.nextInt(); a s.nextInt() s.nextInt s int b = s.nextInt(); b s.nextInt() s.nextInt s int c = s.nextInt(); c s.nextInt() s.nextInt s int d = s.nextInt(); d s.nextInt() s.nextInt s int ans1=0 ans1 0 ans2=0; ans2 0 if(a%d==0) {
				ans1=a/d;
			}
			else {
				ans1=a/d+1;
			} a%d==0 a%d a d 0 {
				ans1=a/d;
			} ans1=a/d ans1 a/d a d {
				ans1=a/d+1;
			} ans1=a/d+1 ans1 a/d+1 a/d a d 1 if(c%b==0) {
				ans2 = c/b;
			}
			else {
				ans2 = c/b+1;
			} c%b==0 c%b c b 0 {
				ans2 = c/b;
			} ans2 = c/b ans2 c/b c b {
				ans2 = c/b+1;
			} ans2 = c/b+1 ans2 c/b+1 c/b c b 1 if(ans1>=ans2) {
				System.out.println("Yes");
			}
			else {
				System.out.println("No");
			} ans1>=ans2 ans1 ans2 {
				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 s = new Scanner(System.in);
		
			int a = s.nextInt();
			int b = s.nextInt();
			int c = s.nextInt();
			int d = s.nextInt();
			
			int ans1=0,ans2=0;
			if(a%d==0) {
				ans1=a/d;
			}
			else {
				ans1=a/d+1;
			}
			if(c%b==0) {
				ans2 = c/b;
			}
			else {
				ans2 = c/b+1;
			}
			if(ans1>=ans2) {
				System.out.println("Yes");
			}
			else {
				System.out.println("No");
			}
			

		
		
	}
} public class Main {
	

	
	public static void main(String[] args) {

		
		Scanner s = new Scanner(System.in);
		
			int a = s.nextInt();
			int b = s.nextInt();
			int c = s.nextInt();
			int d = s.nextInt();
			
			int ans1=0,ans2=0;
			if(a%d==0) {
				ans1=a/d;
			}
			else {
				ans1=a/d+1;
			}
			if(c%b==0) {
				ans2 = c/b;
			}
			else {
				ans2 = c/b+1;
			}
			if(ans1>=ans2) {
				System.out.println("Yes");
			}
			else {
				System.out.println("No");
			}
			

		
		
	}
} Main
import java.util.ArrayList;
import java.util.Scanner;

public class Main {
	

	
	public static void main(String[] args) {

		
		Scanner s = new Scanner(System.in);
		
			int a = s.nextInt();
			int b = s.nextInt();
			int c = s.nextInt();
			int d = s.nextInt();
			
			int ans1=0,ans2=0;
			if(a%d==0) {
				ans1=a/d;
			}
			else {
				ans1=a/d+1;
			}
			if(c%b==0) {
				ans2 = c/b;
			}
			else {
				ans2 = c/b+1;
			}
			if(ans1>=ans2) {
				System.out.println("Yes");
			}
			else {
				System.out.println("No");
			}
			

		
		
	}
}