import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

				Scanner sc = new Scanner(System.in);

				int T_hp = sc.nextInt();
				int T_attack = sc.nextInt();

				int A_hp = sc.nextInt();
				int A_attack = sc.nextInt();


				int A_turn = 0;
				int T_turn =1;
				//どちらかのヒットポイントが0以下になるまで繰り返す。
					while(T_hp > 0 && A_hp > 0) {
					//カウントが1のほうが攻撃を仕掛ける。
						if(T_turn ==1) {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						}else if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						}
					}
				//}
				if(T_hp > 0) {
					System.out.println("Yes");
				}else if(T_hp <= 0) {
					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 T_hp = sc.nextInt();
				int T_attack = sc.nextInt();

				int A_hp = sc.nextInt();
				int A_attack = sc.nextInt();


				int A_turn = 0;
				int T_turn =1;
				//どちらかのヒットポイントが0以下になるまで繰り返す。
					while(T_hp > 0 && A_hp > 0) {
					//カウントが1のほうが攻撃を仕掛ける。
						if(T_turn ==1) {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						}else if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						}
					}
				//}
				if(T_hp > 0) {
					System.out.println("Yes");
				}else if(T_hp <= 0) {
					System.out.println("No");
				}


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

				Scanner sc = new Scanner(System.in);

				int T_hp = sc.nextInt();
				int T_attack = sc.nextInt();

				int A_hp = sc.nextInt();
				int A_attack = sc.nextInt();


				int A_turn = 0;
				int T_turn =1;
				//どちらかのヒットポイントが0以下になるまで繰り返す。
					while(T_hp > 0 && A_hp > 0) {
					//カウントが1のほうが攻撃を仕掛ける。
						if(T_turn ==1) {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						}else if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						}
					}
				//}
				if(T_hp > 0) {
					System.out.println("Yes");
				}else if(T_hp <= 0) {
					System.out.println("No");
				}


			} main {

				Scanner sc = new Scanner(System.in);

				int T_hp = sc.nextInt();
				int T_attack = sc.nextInt();

				int A_hp = sc.nextInt();
				int A_attack = sc.nextInt();


				int A_turn = 0;
				int T_turn =1;
				//どちらかのヒットポイントが0以下になるまで繰り返す。
					while(T_hp > 0 && A_hp > 0) {
					//カウントが1のほうが攻撃を仕掛ける。
						if(T_turn ==1) {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						}else if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						}
					}
				//}
				if(T_hp > 0) {
					System.out.println("Yes");
				}else if(T_hp <= 0) {
					System.out.println("No");
				}


			} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int T_hp = sc.nextInt(); T_hp sc.nextInt() sc.nextInt sc int T_attack = sc.nextInt(); T_attack sc.nextInt() sc.nextInt sc int A_hp = sc.nextInt(); A_hp sc.nextInt() sc.nextInt sc int A_attack = sc.nextInt(); A_attack sc.nextInt() sc.nextInt sc int A_turn = 0; A_turn 0 int T_turn =1; T_turn 1 while(T_hp > 0 && A_hp > 0) {
					//カウントが1のほうが攻撃を仕掛ける。
						if(T_turn ==1) {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						}else if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						}
					} T_hp > 0 && A_hp > 0 T_hp > 0 T_hp 0 A_hp > 0 A_hp 0 {
					//カウントが1のほうが攻撃を仕掛ける。
						if(T_turn ==1) {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						}else if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						}
					} if(T_turn ==1) {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						}else if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						} T_turn ==1 T_turn 1 {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						} A_hp = A_hp - T_attack A_hp A_hp - T_attack A_hp T_attack A_turn = 1 A_turn 1 T_turn = 0 T_turn 0 if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						} A_turn == 1 A_turn 1 {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						} T_hp = T_hp - A_attack T_hp T_hp - A_attack T_hp A_attack T_turn = 1 T_turn 1 A_turn = 0 A_turn 0 if(T_hp > 0) {
					System.out.println("Yes");
				}else if(T_hp <= 0) {
					System.out.println("No");
				} T_hp > 0 T_hp 0 {
					System.out.println("Yes");
				} System.out.println("Yes") System.out.println System.out System System.out "Yes" if(T_hp <= 0) {
					System.out.println("No");
				} T_hp <= 0 T_hp 0 {
					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 sc = new Scanner(System.in);

				int T_hp = sc.nextInt();
				int T_attack = sc.nextInt();

				int A_hp = sc.nextInt();
				int A_attack = sc.nextInt();


				int A_turn = 0;
				int T_turn =1;
				//どちらかのヒットポイントが0以下になるまで繰り返す。
					while(T_hp > 0 && A_hp > 0) {
					//カウントが1のほうが攻撃を仕掛ける。
						if(T_turn ==1) {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						}else if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						}
					}
				//}
				if(T_hp > 0) {
					System.out.println("Yes");
				}else if(T_hp <= 0) {
					System.out.println("No");
				}


			}
		} public class Main {

	public static void main(String[] args) {

				Scanner sc = new Scanner(System.in);

				int T_hp = sc.nextInt();
				int T_attack = sc.nextInt();

				int A_hp = sc.nextInt();
				int A_attack = sc.nextInt();


				int A_turn = 0;
				int T_turn =1;
				//どちらかのヒットポイントが0以下になるまで繰り返す。
					while(T_hp > 0 && A_hp > 0) {
					//カウントが1のほうが攻撃を仕掛ける。
						if(T_turn ==1) {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						}else if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						}
					}
				//}
				if(T_hp > 0) {
					System.out.println("Yes");
				}else if(T_hp <= 0) {
					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 T_hp = sc.nextInt();
				int T_attack = sc.nextInt();

				int A_hp = sc.nextInt();
				int A_attack = sc.nextInt();


				int A_turn = 0;
				int T_turn =1;
				//どちらかのヒットポイントが0以下になるまで繰り返す。
					while(T_hp > 0 && A_hp > 0) {
					//カウントが1のほうが攻撃を仕掛ける。
						if(T_turn ==1) {
							A_hp = A_hp - T_attack;
							A_turn = 1;
							T_turn = 0;
						}else if(A_turn == 1) {
							T_hp = T_hp - A_attack;
							T_turn = 1;
							A_turn = 0;
						}
					}
				//}
				if(T_hp > 0) {
					System.out.println("Yes");
				}else if(T_hp <= 0) {
					System.out.println("No");
				}


			}
		}
