import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		String[] list = scanner.nextLine().split(" ");

		int t_v = Integer.parseInt(list[0]);
		int t_a = Integer.parseInt(list[1]);
		int a_v = Integer.parseInt(list[2]);
		int a_a = Integer.parseInt(list[3]);
		int t_flag = 0;
		int a_flag = 0;


		while(t_v > 0 || a_v > 0) {
			a_v -= t_a;
			if(a_v <= 0) {
				t_flag ++;
				break;
			}
			t_v -= a_a;
			if(t_v <= 0) {
				a_flag ++;
				break;
			}
		}

		if(t_flag == 1) {
			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);
		String[] list = scanner.nextLine().split(" ");

		int t_v = Integer.parseInt(list[0]);
		int t_a = Integer.parseInt(list[1]);
		int a_v = Integer.parseInt(list[2]);
		int a_a = Integer.parseInt(list[3]);
		int t_flag = 0;
		int a_flag = 0;


		while(t_v > 0 || a_v > 0) {
			a_v -= t_a;
			if(a_v <= 0) {
				t_flag ++;
				break;
			}
			t_v -= a_a;
			if(t_v <= 0) {
				a_flag ++;
				break;
			}
		}

		if(t_flag == 1) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}

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

		Scanner scanner = new Scanner(System.in);
		String[] list = scanner.nextLine().split(" ");

		int t_v = Integer.parseInt(list[0]);
		int t_a = Integer.parseInt(list[1]);
		int a_v = Integer.parseInt(list[2]);
		int a_a = Integer.parseInt(list[3]);
		int t_flag = 0;
		int a_flag = 0;


		while(t_v > 0 || a_v > 0) {
			a_v -= t_a;
			if(a_v <= 0) {
				t_flag ++;
				break;
			}
			t_v -= a_a;
			if(t_v <= 0) {
				a_flag ++;
				break;
			}
		}

		if(t_flag == 1) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}

	} main {

		Scanner scanner = new Scanner(System.in);
		String[] list = scanner.nextLine().split(" ");

		int t_v = Integer.parseInt(list[0]);
		int t_a = Integer.parseInt(list[1]);
		int a_v = Integer.parseInt(list[2]);
		int a_a = Integer.parseInt(list[3]);
		int t_flag = 0;
		int a_flag = 0;


		while(t_v > 0 || a_v > 0) {
			a_v -= t_a;
			if(a_v <= 0) {
				t_flag ++;
				break;
			}
			t_v -= a_a;
			if(t_v <= 0) {
				a_flag ++;
				break;
			}
		}

		if(t_flag == 1) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}

	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) String[] list = scanner.nextLine().split(" "); list scanner.nextLine().split(" ") scanner.nextLine().split scanner.nextLine() scanner.nextLine scanner " " int t_v = Integer.parseInt(list[0]); t_v Integer.parseInt(list[0]) Integer.parseInt Integer list[0] list 0 int t_a = Integer.parseInt(list[1]); t_a Integer.parseInt(list[1]) Integer.parseInt Integer list[1] list 1 int a_v = Integer.parseInt(list[2]); a_v Integer.parseInt(list[2]) Integer.parseInt Integer list[2] list 2 int a_a = Integer.parseInt(list[3]); a_a Integer.parseInt(list[3]) Integer.parseInt Integer list[3] list 3 int t_flag = 0; t_flag 0 int a_flag = 0; a_flag 0 while(t_v > 0 || a_v > 0) {
			a_v -= t_a;
			if(a_v <= 0) {
				t_flag ++;
				break;
			}
			t_v -= a_a;
			if(t_v <= 0) {
				a_flag ++;
				break;
			}
		} t_v > 0 || a_v > 0 t_v > 0 t_v 0 a_v > 0 a_v 0 {
			a_v -= t_a;
			if(a_v <= 0) {
				t_flag ++;
				break;
			}
			t_v -= a_a;
			if(t_v <= 0) {
				a_flag ++;
				break;
			}
		} a_v -= t_a a_v t_a if(a_v <= 0) {
				t_flag ++;
				break;
			} a_v <= 0 a_v 0 {
				t_flag ++;
				break;
			} t_flag ++ t_flag break; t_v -= a_a t_v a_a if(t_v <= 0) {
				a_flag ++;
				break;
			} t_v <= 0 t_v 0 {
				a_flag ++;
				break;
			} a_flag ++ a_flag break; if(t_flag == 1) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		} t_flag == 1 t_flag 1 {
			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);
		String[] list = scanner.nextLine().split(" ");

		int t_v = Integer.parseInt(list[0]);
		int t_a = Integer.parseInt(list[1]);
		int a_v = Integer.parseInt(list[2]);
		int a_a = Integer.parseInt(list[3]);
		int t_flag = 0;
		int a_flag = 0;


		while(t_v > 0 || a_v > 0) {
			a_v -= t_a;
			if(a_v <= 0) {
				t_flag ++;
				break;
			}
			t_v -= a_a;
			if(t_v <= 0) {
				a_flag ++;
				break;
			}
		}

		if(t_flag == 1) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}

	}
} public class Main {

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		String[] list = scanner.nextLine().split(" ");

		int t_v = Integer.parseInt(list[0]);
		int t_a = Integer.parseInt(list[1]);
		int a_v = Integer.parseInt(list[2]);
		int a_a = Integer.parseInt(list[3]);
		int t_flag = 0;
		int a_flag = 0;


		while(t_v > 0 || a_v > 0) {
			a_v -= t_a;
			if(a_v <= 0) {
				t_flag ++;
				break;
			}
			t_v -= a_a;
			if(t_v <= 0) {
				a_flag ++;
				break;
			}
		}

		if(t_flag == 1) {
			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);
		String[] list = scanner.nextLine().split(" ");

		int t_v = Integer.parseInt(list[0]);
		int t_a = Integer.parseInt(list[1]);
		int a_v = Integer.parseInt(list[2]);
		int a_a = Integer.parseInt(list[3]);
		int t_flag = 0;
		int a_flag = 0;


		while(t_v > 0 || a_v > 0) {
			a_v -= t_a;
			if(a_v <= 0) {
				t_flag ++;
				break;
			}
			t_v -= a_a;
			if(t_v <= 0) {
				a_flag ++;
				break;
			}
		}

		if(t_flag == 1) {
			System.out.println("Yes");
		}else {
			System.out.println("No");
		}

	}
}