import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int t_hp = Integer.parseInt(sc.next());
        int t_atk = Integer.parseInt(sc.next());
        int a_hp = Integer.parseInt(sc.next());
        int a_atk = Integer.parseInt(sc.next());
        boolean t_victory = false;
        while ((t_hp > 0) || (a_hp > 0)) {
            a_hp -= t_atk;
            if (a_hp <= 0) {
                t_victory = true;
                break;
            }
            t_hp -= a_atk;
            if (t_hp <= 0) {
                break;
            }
        }
        if (t_victory) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

        sc.close();
    }

} 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 = Integer.parseInt(sc.next());
        int t_atk = Integer.parseInt(sc.next());
        int a_hp = Integer.parseInt(sc.next());
        int a_atk = Integer.parseInt(sc.next());
        boolean t_victory = false;
        while ((t_hp > 0) || (a_hp > 0)) {
            a_hp -= t_atk;
            if (a_hp <= 0) {
                t_victory = true;
                break;
            }
            t_hp -= a_atk;
            if (t_hp <= 0) {
                break;
            }
        }
        if (t_victory) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

        sc.close();
    }

} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int t_hp = Integer.parseInt(sc.next());
        int t_atk = Integer.parseInt(sc.next());
        int a_hp = Integer.parseInt(sc.next());
        int a_atk = Integer.parseInt(sc.next());
        boolean t_victory = false;
        while ((t_hp > 0) || (a_hp > 0)) {
            a_hp -= t_atk;
            if (a_hp <= 0) {
                t_victory = true;
                break;
            }
            t_hp -= a_atk;
            if (t_hp <= 0) {
                break;
            }
        }
        if (t_victory) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        int t_hp = Integer.parseInt(sc.next());
        int t_atk = Integer.parseInt(sc.next());
        int a_hp = Integer.parseInt(sc.next());
        int a_atk = Integer.parseInt(sc.next());
        boolean t_victory = false;
        while ((t_hp > 0) || (a_hp > 0)) {
            a_hp -= t_atk;
            if (a_hp <= 0) {
                t_victory = true;
                break;
            }
            t_hp -= a_atk;
            if (t_hp <= 0) {
                break;
            }
        }
        if (t_victory) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int t_hp = Integer.parseInt(sc.next()); t_hp Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int t_atk = Integer.parseInt(sc.next()); t_atk Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int a_hp = Integer.parseInt(sc.next()); a_hp Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int a_atk = Integer.parseInt(sc.next()); a_atk Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc boolean t_victory = false; t_victory false while ((t_hp > 0) || (a_hp > 0)) {
            a_hp -= t_atk;
            if (a_hp <= 0) {
                t_victory = true;
                break;
            }
            t_hp -= a_atk;
            if (t_hp <= 0) {
                break;
            }
        } (t_hp > 0) || (a_hp > 0) (t_hp > 0) t_hp 0 (a_hp > 0) a_hp 0 {
            a_hp -= t_atk;
            if (a_hp <= 0) {
                t_victory = true;
                break;
            }
            t_hp -= a_atk;
            if (t_hp <= 0) {
                break;
            }
        } a_hp -= t_atk a_hp t_atk if (a_hp <= 0) {
                t_victory = true;
                break;
            } a_hp <= 0 a_hp 0 {
                t_victory = true;
                break;
            } t_victory = true t_victory true break; t_hp -= a_atk t_hp a_atk if (t_hp <= 0) {
                break;
            } t_hp <= 0 t_hp 0 {
                break;
            } break; if (t_victory) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        } t_victory {
            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" sc.close() sc.close sc String[] args args public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int t_hp = Integer.parseInt(sc.next());
        int t_atk = Integer.parseInt(sc.next());
        int a_hp = Integer.parseInt(sc.next());
        int a_atk = Integer.parseInt(sc.next());
        boolean t_victory = false;
        while ((t_hp > 0) || (a_hp > 0)) {
            a_hp -= t_atk;
            if (a_hp <= 0) {
                t_victory = true;
                break;
            }
            t_hp -= a_atk;
            if (t_hp <= 0) {
                break;
            }
        }
        if (t_victory) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

        sc.close();
    }

} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int t_hp = Integer.parseInt(sc.next());
        int t_atk = Integer.parseInt(sc.next());
        int a_hp = Integer.parseInt(sc.next());
        int a_atk = Integer.parseInt(sc.next());
        boolean t_victory = false;
        while ((t_hp > 0) || (a_hp > 0)) {
            a_hp -= t_atk;
            if (a_hp <= 0) {
                t_victory = true;
                break;
            }
            t_hp -= a_atk;
            if (t_hp <= 0) {
                break;
            }
        }
        if (t_victory) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

        sc.close();
    }

} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int t_hp = Integer.parseInt(sc.next());
        int t_atk = Integer.parseInt(sc.next());
        int a_hp = Integer.parseInt(sc.next());
        int a_atk = Integer.parseInt(sc.next());
        boolean t_victory = false;
        while ((t_hp > 0) || (a_hp > 0)) {
            a_hp -= t_atk;
            if (a_hp <= 0) {
                t_victory = true;
                break;
            }
            t_hp -= a_atk;
            if (t_hp <= 0) {
                break;
            }
        }
        if (t_victory) {
            System.out.println("Yes");
        } else {
            System.out.println("No");
        }

        sc.close();
    }

}
