import java.util.Scanner;

class Main {
	public static void main(String args[]) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int count = 0;

		while (true) {
			if ((count % 2) == 0) {
				C -= B;
				if (C <= 0) {
					System.out.println("Yes");
					break;
				}
			} else {
				A -= D;
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
			count++;
		}
	}
} import java.util.Scanner; Scanner java.util class Main {
	public static void main(String args[]) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int count = 0;

		while (true) {
			if ((count % 2) == 0) {
				C -= B;
				if (C <= 0) {
					System.out.println("Yes");
					break;
				}
			} else {
				A -= D;
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
			count++;
		}
	}
} Main public static void main(String args[]) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int count = 0;

		while (true) {
			if ((count % 2) == 0) {
				C -= B;
				if (C <= 0) {
					System.out.println("Yes");
					break;
				}
			} else {
				A -= D;
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
			count++;
		}
	} main {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int count = 0;

		while (true) {
			if ((count % 2) == 0) {
				C -= B;
				if (C <= 0) {
					System.out.println("Yes");
					break;
				}
			} else {
				A -= D;
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
			count++;
		}
	} 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 int count = 0; count 0 while (true) {
			if ((count % 2) == 0) {
				C -= B;
				if (C <= 0) {
					System.out.println("Yes");
					break;
				}
			} else {
				A -= D;
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
			count++;
		} true {
			if ((count % 2) == 0) {
				C -= B;
				if (C <= 0) {
					System.out.println("Yes");
					break;
				}
			} else {
				A -= D;
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
			count++;
		} if ((count % 2) == 0) {
				C -= B;
				if (C <= 0) {
					System.out.println("Yes");
					break;
				}
			} else {
				A -= D;
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			} (count % 2) == 0 (count % 2) count 2 0 {
				C -= B;
				if (C <= 0) {
					System.out.println("Yes");
					break;
				}
			} C -= B C B if (C <= 0) {
					System.out.println("Yes");
					break;
				} C <= 0 C 0 {
					System.out.println("Yes");
					break;
				} System.out.println("Yes") System.out.println System.out System System.out "Yes" break; {
				A -= D;
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			} A -= D A D if (A <= 0) {
					System.out.println("No");
					break;
				} A <= 0 A 0 {
					System.out.println("No");
					break;
				} System.out.println("No") System.out.println System.out System System.out "No" break; count++ count String args[] args
import java.util.Scanner;

class Main {
	public static void main(String args[]) {
		Scanner scan = new Scanner(System.in);
		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		int count = 0;

		while (true) {
			if ((count % 2) == 0) {
				C -= B;
				if (C <= 0) {
					System.out.println("Yes");
					break;
				}
			} else {
				A -= D;
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
			count++;
		}
	}
}