import java.util.Scanner;
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();
		if (1<=A&&A<=100 &&1<=B&&B<=100 &&1<=C&&C<=100 &&1<=D&&D<=100 ){
		}
		else{
			throw new IllegalArgumentException("不適切な数値です。");
		}
		while(A> 0 && C> 0){	
			C -= B;
			if (C > 0){
				A -= D;
			}else{
				System.out.println("Yes");
				return;
			}
		}
			System.out.println("No");
	}
	
} import java.util.Scanner; Scanner 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();
		if (1<=A&&A<=100 &&1<=B&&B<=100 &&1<=C&&C<=100 &&1<=D&&D<=100 ){
		}
		else{
			throw new IllegalArgumentException("不適切な数値です。");
		}
		while(A> 0 && C> 0){	
			C -= B;
			if (C > 0){
				A -= D;
			}else{
				System.out.println("Yes");
				return;
			}
		}
			System.out.println("No");
	}
	
} 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();
		if (1<=A&&A<=100 &&1<=B&&B<=100 &&1<=C&&C<=100 &&1<=D&&D<=100 ){
		}
		else{
			throw new IllegalArgumentException("不適切な数値です。");
		}
		while(A> 0 && C> 0){	
			C -= B;
			if (C > 0){
				A -= D;
			}else{
				System.out.println("Yes");
				return;
			}
		}
			System.out.println("No");
	} main {
		Scanner sc = new Scanner(System.in);
		int A = sc.nextInt();
		int B = sc.nextInt();
		int C = sc.nextInt();
		int D = sc.nextInt();
		if (1<=A&&A<=100 &&1<=B&&B<=100 &&1<=C&&C<=100 &&1<=D&&D<=100 ){
		}
		else{
			throw new IllegalArgumentException("不適切な数値です。");
		}
		while(A> 0 && C> 0){	
			C -= B;
			if (C > 0){
				A -= D;
			}else{
				System.out.println("Yes");
				return;
			}
		}
			System.out.println("No");
	} 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 if (1<=A&&A<=100 &&1<=B&&B<=100 &&1<=C&&C<=100 &&1<=D&&D<=100 ){
		}
		else{
			throw new IllegalArgumentException("不適切な数値です。");
		} 1<=A&&A<=100 &&1<=B&&B<=100 &&1<=C&&C<=100 &&1<=D&&D<=100 1<=D C<=100 1<=C B<=100 1<=B 1<=A&&A<=100 &&1<=B&&B<=100 &&1<=C&&C<=100 &&1<=D&&D<=100 1<=A 1 A A<=100 A 100 1<=B 1 B B<=100 B 100 1<=C 1 C C<=100 C 100 1<=D 1 D D<=100 D 100 {
		} {
			throw new IllegalArgumentException("不適切な数値です。");
		} throw new IllegalArgumentException("不適切な数値です。"); new IllegalArgumentException("不適切な数値です。") while(A> 0 && C> 0){	
			C -= B;
			if (C > 0){
				A -= D;
			}else{
				System.out.println("Yes");
				return;
			}
		} A> 0 && C> 0 A> 0 A 0 C> 0 C 0 {	
			C -= B;
			if (C > 0){
				A -= D;
			}else{
				System.out.println("Yes");
				return;
			}
		} C -= B C B if (C > 0){
				A -= D;
			}else{
				System.out.println("Yes");
				return;
			} C > 0 C 0 {
				A -= D;
			} A -= D A D {
				System.out.println("Yes");
				return;
			} System.out.println("Yes") System.out.println System.out System System.out "Yes" return; 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 sc = new Scanner(System.in);
		int A = sc.nextInt();
		int B = sc.nextInt();
		int C = sc.nextInt();
		int D = sc.nextInt();
		if (1<=A&&A<=100 &&1<=B&&B<=100 &&1<=C&&C<=100 &&1<=D&&D<=100 ){
		}
		else{
			throw new IllegalArgumentException("不適切な数値です。");
		}
		while(A> 0 && C> 0){	
			C -= B;
			if (C > 0){
				A -= D;
			}else{
				System.out.println("Yes");
				return;
			}
		}
			System.out.println("No");
	}
	
} 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();
		if (1<=A&&A<=100 &&1<=B&&B<=100 &&1<=C&&C<=100 &&1<=D&&D<=100 ){
		}
		else{
			throw new IllegalArgumentException("不適切な数値です。");
		}
		while(A> 0 && C> 0){	
			C -= B;
			if (C > 0){
				A -= D;
			}else{
				System.out.println("Yes");
				return;
			}
		}
			System.out.println("No");
	}
	
} Main
import java.util.Scanner;
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();
		if (1<=A&&A<=100 &&1<=B&&B<=100 &&1<=C&&C<=100 &&1<=D&&D<=100 ){
		}
		else{
			throw new IllegalArgumentException("不適切な数値です。");
		}
		while(A> 0 && C> 0){	
			C -= B;
			if (C > 0){
				A -= D;
			}else{
				System.out.println("Yes");
				return;
			}
		}
			System.out.println("No");
	}
	
}