import 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 p = 0;
		while(a > 0 && c > 0){
			if(p == 0)
				c -= b;
			else
				a -= d;
			p = 1 - p;
		}
		System.out.println((a > 0)?"Yes":"No");
		
		sc.close();
    }
} import java.util.*; util.* java 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 p = 0;
		while(a > 0 && c > 0){
			if(p == 0)
				c -= b;
			else
				a -= d;
			p = 1 - p;
		}
		System.out.println((a > 0)?"Yes":"No");
		
		sc.close();
    }
} 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 p = 0;
		while(a > 0 && c > 0){
			if(p == 0)
				c -= b;
			else
				a -= d;
			p = 1 - p;
		}
		System.out.println((a > 0)?"Yes":"No");
		
		sc.close();
    } main {
    	Scanner sc = new Scanner(System.in);
		
		int a = sc.nextInt();
		int b = sc.nextInt();
		int c = sc.nextInt();
		int d = sc.nextInt();
		int p = 0;
		while(a > 0 && c > 0){
			if(p == 0)
				c -= b;
			else
				a -= d;
			p = 1 - p;
		}
		System.out.println((a > 0)?"Yes":"No");
		
		sc.close();
    } 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 p = 0; p 0 while(a > 0 && c > 0){
			if(p == 0)
				c -= b;
			else
				a -= d;
			p = 1 - p;
		} a > 0 && c > 0 a > 0 a 0 c > 0 c 0 {
			if(p == 0)
				c -= b;
			else
				a -= d;
			p = 1 - p;
		} if(p == 0)
				c -= b;
			else
				a -= d; p == 0 p 0 c -= b c b a -= d a d p = 1 - p p 1 - p 1 p System.out.println((a > 0)?"Yes":"No") System.out.println System.out System System.out (a > 0)?"Yes":"No" (a > 0) a 0 "Yes" "No" sc.close() sc.close sc 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 p = 0;
		while(a > 0 && c > 0){
			if(p == 0)
				c -= b;
			else
				a -= d;
			p = 1 - p;
		}
		System.out.println((a > 0)?"Yes":"No");
		
		sc.close();
    }
} 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 p = 0;
		while(a > 0 && c > 0){
			if(p == 0)
				c -= b;
			else
				a -= d;
			p = 1 - p;
		}
		System.out.println((a > 0)?"Yes":"No");
		
		sc.close();
    }
} Main
import 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 p = 0;
		while(a > 0 && c > 0){
			if(p == 0)
				c -= b;
			else
				a -= d;
			p = 1 - p;
		}
		System.out.println((a > 0)?"Yes":"No");
		
		sc.close();
    }
}