import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashi_hp = sc.nextInt();
        int takahashi_att = sc.nextInt();
        int aoki_hp = sc.nextInt();
        int aoki_att = sc.nextInt();
        while (true) {
            aoki_hp -= takahashi_att;
            if (aoki_hp <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashi_hp -= aoki_att;
            if (takahashi_hp <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashi_hp = sc.nextInt();
        int takahashi_att = sc.nextInt();
        int aoki_hp = sc.nextInt();
        int aoki_att = sc.nextInt();
        while (true) {
            aoki_hp -= takahashi_att;
            if (aoki_hp <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashi_hp -= aoki_att;
            if (takahashi_hp <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashi_hp = sc.nextInt();
        int takahashi_att = sc.nextInt();
        int aoki_hp = sc.nextInt();
        int aoki_att = sc.nextInt();
        while (true) {
            aoki_hp -= takahashi_att;
            if (aoki_hp <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashi_hp -= aoki_att;
            if (takahashi_hp <= 0) {
                System.out.println("No");
                break;
            }
        }
    } main {
        Scanner sc = new Scanner(System.in);
        int takahashi_hp = sc.nextInt();
        int takahashi_att = sc.nextInt();
        int aoki_hp = sc.nextInt();
        int aoki_att = sc.nextInt();
        while (true) {
            aoki_hp -= takahashi_att;
            if (aoki_hp <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashi_hp -= aoki_att;
            if (takahashi_hp <= 0) {
                System.out.println("No");
                break;
            }
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int takahashi_hp = sc.nextInt(); takahashi_hp sc.nextInt() sc.nextInt sc int takahashi_att = sc.nextInt(); takahashi_att sc.nextInt() sc.nextInt sc int aoki_hp = sc.nextInt(); aoki_hp sc.nextInt() sc.nextInt sc int aoki_att = sc.nextInt(); aoki_att sc.nextInt() sc.nextInt sc while (true) {
            aoki_hp -= takahashi_att;
            if (aoki_hp <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashi_hp -= aoki_att;
            if (takahashi_hp <= 0) {
                System.out.println("No");
                break;
            }
        } true {
            aoki_hp -= takahashi_att;
            if (aoki_hp <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashi_hp -= aoki_att;
            if (takahashi_hp <= 0) {
                System.out.println("No");
                break;
            }
        } aoki_hp -= takahashi_att aoki_hp takahashi_att if (aoki_hp <= 0) {
                System.out.println("Yes");
                break;
            } aoki_hp <= 0 aoki_hp 0 {
                System.out.println("Yes");
                break;
            } System.out.println("Yes") System.out.println System.out System System.out "Yes" break; takahashi_hp -= aoki_att takahashi_hp aoki_att if (takahashi_hp <= 0) {
                System.out.println("No");
                break;
            } takahashi_hp <= 0 takahashi_hp 0 {
                System.out.println("No");
                break;
            } System.out.println("No") System.out.println System.out System System.out "No" break; String[] args args public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashi_hp = sc.nextInt();
        int takahashi_att = sc.nextInt();
        int aoki_hp = sc.nextInt();
        int aoki_att = sc.nextInt();
        while (true) {
            aoki_hp -= takahashi_att;
            if (aoki_hp <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashi_hp -= aoki_att;
            if (takahashi_hp <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashi_hp = sc.nextInt();
        int takahashi_att = sc.nextInt();
        int aoki_hp = sc.nextInt();
        int aoki_att = sc.nextInt();
        while (true) {
            aoki_hp -= takahashi_att;
            if (aoki_hp <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashi_hp -= aoki_att;
            if (takahashi_hp <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} Main
import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int takahashi_hp = sc.nextInt();
        int takahashi_att = sc.nextInt();
        int aoki_hp = sc.nextInt();
        int aoki_att = sc.nextInt();
        while (true) {
            aoki_hp -= takahashi_att;
            if (aoki_hp <= 0) {
                System.out.println("Yes");
                break;
            }
            takahashi_hp -= aoki_att;
            if (takahashi_hp <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
}
