import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scan = new Scanner(System.in);

		int a = scan.nextInt();
		int b = scan.nextInt();
		int c = scan.nextInt();
		int d = scan.nextInt();

do {

	c -= b;
	if(c <= 0)break;
	a -= d;
}while(a >0);

System.out.println(a>0? "Yes" : "No");
		scan.close();

	}

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

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scan = new Scanner(System.in);

		int a = scan.nextInt();
		int b = scan.nextInt();
		int c = scan.nextInt();
		int d = scan.nextInt();

do {

	c -= b;
	if(c <= 0)break;
	a -= d;
}while(a >0);

System.out.println(a>0? "Yes" : "No");
		scan.close();

	}

} Main public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scan = new Scanner(System.in);

		int a = scan.nextInt();
		int b = scan.nextInt();
		int c = scan.nextInt();
		int d = scan.nextInt();

do {

	c -= b;
	if(c <= 0)break;
	a -= d;
}while(a >0);

System.out.println(a>0? "Yes" : "No");
		scan.close();

	} main {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scan = new Scanner(System.in);

		int a = scan.nextInt();
		int b = scan.nextInt();
		int c = scan.nextInt();
		int d = scan.nextInt();

do {

	c -= b;
	if(c <= 0)break;
	a -= d;
}while(a >0);

System.out.println(a>0? "Yes" : "No");
		scan.close();

	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int a = scan.nextInt(); a scan.nextInt() scan.nextInt scan int b = scan.nextInt(); b scan.nextInt() scan.nextInt scan int c = scan.nextInt(); c scan.nextInt() scan.nextInt scan int d = scan.nextInt(); d scan.nextInt() scan.nextInt scan do {

	c -= b;
	if(c <= 0)break;
	a -= d;
}while(a >0); a >0 a 0 {

	c -= b;
	if(c <= 0)break;
	a -= d;
} c -= b c b if(c <= 0)break; c <= 0 c 0 break; a -= d a d 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" scan.close() scan.close scan String[] args args public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scan = new Scanner(System.in);

		int a = scan.nextInt();
		int b = scan.nextInt();
		int c = scan.nextInt();
		int d = scan.nextInt();

do {

	c -= b;
	if(c <= 0)break;
	a -= d;
}while(a >0);

System.out.println(a>0? "Yes" : "No");
		scan.close();

	}

} public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scan = new Scanner(System.in);

		int a = scan.nextInt();
		int b = scan.nextInt();
		int c = scan.nextInt();
		int d = scan.nextInt();

do {

	c -= b;
	if(c <= 0)break;
	a -= d;
}while(a >0);

System.out.println(a>0? "Yes" : "No");
		scan.close();

	}

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

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner scan = new Scanner(System.in);

		int a = scan.nextInt();
		int b = scan.nextInt();
		int c = scan.nextInt();
		int d = scan.nextInt();

do {

	c -= b;
	if(c <= 0)break;
	a -= d;
}while(a >0);

System.out.println(a>0? "Yes" : "No");
		scan.close();

	}

}
