import java.util.Scanner;

public class Main {
	
	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		
		int THP = scanner.nextInt();
		int TAP = scanner.nextInt();
		int AHP = scanner.nextInt();
		int AAP = scanner.nextInt();
		
		scanner.close();
		
		int TC = AHP/TAP;
		int TCP = AHP%TAP;
		if (TCP != 0) {
			TC = TC + 1;
		}
		
		int AC = THP/AAP;
		int ACP = THP%AAP;
		
		if (ACP != 0) {
			AC = AC + 1;
		}
		
		if (TC == AC) {
			System.out.println("Yes");
		} else if (TC < AC) {
			System.out.println("Yes");
		} else if (TC + 1 == AC) {
			System.out.println("Yes"); 
		} else {
			System.out.println("No");
		}
	}

} import java.util.Scanner; Scanner java.util public class Main {
	
	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		
		int THP = scanner.nextInt();
		int TAP = scanner.nextInt();
		int AHP = scanner.nextInt();
		int AAP = scanner.nextInt();
		
		scanner.close();
		
		int TC = AHP/TAP;
		int TCP = AHP%TAP;
		if (TCP != 0) {
			TC = TC + 1;
		}
		
		int AC = THP/AAP;
		int ACP = THP%AAP;
		
		if (ACP != 0) {
			AC = AC + 1;
		}
		
		if (TC == AC) {
			System.out.println("Yes");
		} else if (TC < AC) {
			System.out.println("Yes");
		} else if (TC + 1 == AC) {
			System.out.println("Yes"); 
		} else {
			System.out.println("No");
		}
	}

} Main public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		
		int THP = scanner.nextInt();
		int TAP = scanner.nextInt();
		int AHP = scanner.nextInt();
		int AAP = scanner.nextInt();
		
		scanner.close();
		
		int TC = AHP/TAP;
		int TCP = AHP%TAP;
		if (TCP != 0) {
			TC = TC + 1;
		}
		
		int AC = THP/AAP;
		int ACP = THP%AAP;
		
		if (ACP != 0) {
			AC = AC + 1;
		}
		
		if (TC == AC) {
			System.out.println("Yes");
		} else if (TC < AC) {
			System.out.println("Yes");
		} else if (TC + 1 == AC) {
			System.out.println("Yes"); 
		} else {
			System.out.println("No");
		}
	} main {
		
		Scanner scanner = new Scanner(System.in);
		
		int THP = scanner.nextInt();
		int TAP = scanner.nextInt();
		int AHP = scanner.nextInt();
		int AAP = scanner.nextInt();
		
		scanner.close();
		
		int TC = AHP/TAP;
		int TCP = AHP%TAP;
		if (TCP != 0) {
			TC = TC + 1;
		}
		
		int AC = THP/AAP;
		int ACP = THP%AAP;
		
		if (ACP != 0) {
			AC = AC + 1;
		}
		
		if (TC == AC) {
			System.out.println("Yes");
		} else if (TC < AC) {
			System.out.println("Yes");
		} else if (TC + 1 == AC) {
			System.out.println("Yes"); 
		} else {
			System.out.println("No");
		}
	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int THP = scanner.nextInt(); THP scanner.nextInt() scanner.nextInt scanner int TAP = scanner.nextInt(); TAP scanner.nextInt() scanner.nextInt scanner int AHP = scanner.nextInt(); AHP scanner.nextInt() scanner.nextInt scanner int AAP = scanner.nextInt(); AAP scanner.nextInt() scanner.nextInt scanner scanner.close() scanner.close scanner int TC = AHP/TAP; TC AHP/TAP AHP TAP int TCP = AHP%TAP; TCP AHP%TAP AHP TAP if (TCP != 0) {
			TC = TC + 1;
		} TCP != 0 TCP 0 {
			TC = TC + 1;
		} TC = TC + 1 TC TC + 1 TC 1 int AC = THP/AAP; AC THP/AAP THP AAP int ACP = THP%AAP; ACP THP%AAP THP AAP if (ACP != 0) {
			AC = AC + 1;
		} ACP != 0 ACP 0 {
			AC = AC + 1;
		} AC = AC + 1 AC AC + 1 AC 1 if (TC == AC) {
			System.out.println("Yes");
		} else if (TC < AC) {
			System.out.println("Yes");
		} else if (TC + 1 == AC) {
			System.out.println("Yes"); 
		} else {
			System.out.println("No");
		} TC == AC TC AC {
			System.out.println("Yes");
		} System.out.println("Yes") System.out.println System.out System System.out "Yes" if (TC < AC) {
			System.out.println("Yes");
		} else if (TC + 1 == AC) {
			System.out.println("Yes"); 
		} else {
			System.out.println("No");
		} TC < AC TC AC {
			System.out.println("Yes");
		} System.out.println("Yes") System.out.println System.out System System.out "Yes" if (TC + 1 == AC) {
			System.out.println("Yes"); 
		} else {
			System.out.println("No");
		} TC + 1 == AC TC + 1 TC 1 AC {
			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 scanner = new Scanner(System.in);
		
		int THP = scanner.nextInt();
		int TAP = scanner.nextInt();
		int AHP = scanner.nextInt();
		int AAP = scanner.nextInt();
		
		scanner.close();
		
		int TC = AHP/TAP;
		int TCP = AHP%TAP;
		if (TCP != 0) {
			TC = TC + 1;
		}
		
		int AC = THP/AAP;
		int ACP = THP%AAP;
		
		if (ACP != 0) {
			AC = AC + 1;
		}
		
		if (TC == AC) {
			System.out.println("Yes");
		} else if (TC < AC) {
			System.out.println("Yes");
		} else if (TC + 1 == AC) {
			System.out.println("Yes"); 
		} else {
			System.out.println("No");
		}
	}

} public class Main {
	
	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		
		int THP = scanner.nextInt();
		int TAP = scanner.nextInt();
		int AHP = scanner.nextInt();
		int AAP = scanner.nextInt();
		
		scanner.close();
		
		int TC = AHP/TAP;
		int TCP = AHP%TAP;
		if (TCP != 0) {
			TC = TC + 1;
		}
		
		int AC = THP/AAP;
		int ACP = THP%AAP;
		
		if (ACP != 0) {
			AC = AC + 1;
		}
		
		if (TC == AC) {
			System.out.println("Yes");
		} else if (TC < AC) {
			System.out.println("Yes");
		} else if (TC + 1 == AC) {
			System.out.println("Yes"); 
		} else {
			System.out.println("No");
		}
	}

} Main
import java.util.Scanner;

public class Main {
	
	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		
		int THP = scanner.nextInt();
		int TAP = scanner.nextInt();
		int AHP = scanner.nextInt();
		int AAP = scanner.nextInt();
		
		scanner.close();
		
		int TC = AHP/TAP;
		int TCP = AHP%TAP;
		if (TCP != 0) {
			TC = TC + 1;
		}
		
		int AC = THP/AAP;
		int ACP = THP%AAP;
		
		if (ACP != 0) {
			AC = AC + 1;
		}
		
		if (TC == AC) {
			System.out.println("Yes");
		} else if (TC < AC) {
			System.out.println("Yes");
		} else if (TC + 1 == AC) {
			System.out.println("Yes"); 
		} else {
			System.out.println("No");
		}
	}

}
