import java.util.Scanner;

public 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();

		while (true) {
			C = atk(B, C);
			if (C <= 0) {
				System.out.println("Yes");
				break;
			} else {
				A = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
		}


	}

	public static int atk(int atk, int hp) {

		hp -= atk;

		return hp;
	}

}
 import java.util.Scanner; Scanner java.util public 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();

		while (true) {
			C = atk(B, C);
			if (C <= 0) {
				System.out.println("Yes");
				break;
			} else {
				A = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
		}


	}

	public static int atk(int atk, int hp) {

		hp -= atk;

		return hp;
	}

} 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();

		while (true) {
			C = atk(B, C);
			if (C <= 0) {
				System.out.println("Yes");
				break;
			} else {
				A = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
		}


	} main {

		Scanner scan = new Scanner(System.in);

		int A = scan.nextInt();
		int B = scan.nextInt();
		int C = scan.nextInt();
		int D = scan.nextInt();

		while (true) {
			C = atk(B, C);
			if (C <= 0) {
				System.out.println("Yes");
				break;
			} else {
				A = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
		}


	} 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 while (true) {
			C = atk(B, C);
			if (C <= 0) {
				System.out.println("Yes");
				break;
			} else {
				A = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
		} true {
			C = atk(B, C);
			if (C <= 0) {
				System.out.println("Yes");
				break;
			} else {
				A = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
		} C = atk(B, C) C atk(B, C) atk B C if (C <= 0) {
				System.out.println("Yes");
				break;
			} else {
				A = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					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 = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			} A = atk(D, A) A atk(D, A) atk D A 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; String[] args args public static int atk(int atk, int hp) {

		hp -= atk;

		return hp;
	} atk {

		hp -= atk;

		return hp;
	} hp -= atk hp atk return hp; hp int atk atk int hp hp public 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();

		while (true) {
			C = atk(B, C);
			if (C <= 0) {
				System.out.println("Yes");
				break;
			} else {
				A = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
		}


	}

	public static int atk(int atk, int hp) {

		hp -= atk;

		return hp;
	}

} public 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();

		while (true) {
			C = atk(B, C);
			if (C <= 0) {
				System.out.println("Yes");
				break;
			} else {
				A = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
		}


	}

	public static int atk(int atk, int hp) {

		hp -= atk;

		return hp;
	}

} Main
import java.util.Scanner;

public 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();

		while (true) {
			C = atk(B, C);
			if (C <= 0) {
				System.out.println("Yes");
				break;
			} else {
				A = atk(D, A);
				if (A <= 0) {
					System.out.println("No");
					break;
				}
			}
		}


	}

	public static int atk(int atk, int hp) {

		hp -= atk;

		return hp;
	}

}

