import java.util.*;

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

        Scanner sc = new Scanner(System.in);
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        int c = Integer.parseInt(sc.next());
        int d = Integer.parseInt(sc.next());

        while (a > 0 && c > 0) {
            c -= b;
            if (c <= 0) {
                System.out.println("Yes");
                break;
            }
            a -= d;
            if (a <= 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 a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        int c = Integer.parseInt(sc.next());
        int d = Integer.parseInt(sc.next());

        while (a > 0 && c > 0) {
            c -= b;
            if (c <= 0) {
                System.out.println("Yes");
                break;
            }
            a -= d;
            if (a <= 0) {
                System.out.println("No");
                break;
            }
        }

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

        Scanner sc = new Scanner(System.in);
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        int c = Integer.parseInt(sc.next());
        int d = Integer.parseInt(sc.next());

        while (a > 0 && c > 0) {
            c -= b;
            if (c <= 0) {
                System.out.println("Yes");
                break;
            }
            a -= d;
            if (a <= 0) {
                System.out.println("No");
                break;
            }
        }

    } main {

        Scanner sc = new Scanner(System.in);
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        int c = Integer.parseInt(sc.next());
        int d = Integer.parseInt(sc.next());

        while (a > 0 && c > 0) {
            c -= b;
            if (c <= 0) {
                System.out.println("Yes");
                break;
            }
            a -= d;
            if (a <= 0) {
                System.out.println("No");
                break;
            }
        }

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a = Integer.parseInt(sc.next()); a Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int b = Integer.parseInt(sc.next()); b Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int c = Integer.parseInt(sc.next()); c Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int d = Integer.parseInt(sc.next()); d Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc while (a > 0 && c > 0) {
            c -= b;
            if (c <= 0) {
                System.out.println("Yes");
                break;
            }
            a -= d;
            if (a <= 0) {
                System.out.println("No");
                break;
            }
        } a > 0 && c > 0 a > 0 a 0 c > 0 c 0 {
            c -= b;
            if (c <= 0) {
                System.out.println("Yes");
                break;
            }
            a -= d;
            if (a <= 0) {
                System.out.println("No");
                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 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; String[] args args public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        int c = Integer.parseInt(sc.next());
        int d = Integer.parseInt(sc.next());

        while (a > 0 && c > 0) {
            c -= b;
            if (c <= 0) {
                System.out.println("Yes");
                break;
            }
            a -= d;
            if (a <= 0) {
                System.out.println("No");
                break;
            }
        }

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

        Scanner sc = new Scanner(System.in);
        int a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        int c = Integer.parseInt(sc.next());
        int d = Integer.parseInt(sc.next());

        while (a > 0 && c > 0) {
            c -= b;
            if (c <= 0) {
                System.out.println("Yes");
                break;
            }
            a -= d;
            if (a <= 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 a = Integer.parseInt(sc.next());
        int b = Integer.parseInt(sc.next());
        int c = Integer.parseInt(sc.next());
        int d = Integer.parseInt(sc.next());

        while (a > 0 && c > 0) {
            c -= b;
            if (c <= 0) {
                System.out.println("Yes");
                break;
            }
            a -= d;
            if (a <= 0) {
                System.out.println("No");
                break;
            }
        }

    }
}
