import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        String[] in = s.nextLine().split(" ");
        int A = Integer.parseInt(in[0]);
        int B = Integer.parseInt(in[1]);
        int C = Integer.parseInt(in[2]);
        int D = Integer.parseInt(in[3]);

        while (true) {
            C -= B;
            if (C <= 0) {
                System.out.println("Yes");
                break;
            }

            A -= D;
            if (A <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        String[] in = s.nextLine().split(" ");
        int A = Integer.parseInt(in[0]);
        int B = Integer.parseInt(in[1]);
        int C = Integer.parseInt(in[2]);
        int D = Integer.parseInt(in[3]);

        while (true) {
            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 s = new Scanner(System.in);
        String[] in = s.nextLine().split(" ");
        int A = Integer.parseInt(in[0]);
        int B = Integer.parseInt(in[1]);
        int C = Integer.parseInt(in[2]);
        int D = Integer.parseInt(in[3]);

        while (true) {
            C -= B;
            if (C <= 0) {
                System.out.println("Yes");
                break;
            }

            A -= D;
            if (A <= 0) {
                System.out.println("No");
                break;
            }
        }
    } main {
        Scanner s = new Scanner(System.in);
        String[] in = s.nextLine().split(" ");
        int A = Integer.parseInt(in[0]);
        int B = Integer.parseInt(in[1]);
        int C = Integer.parseInt(in[2]);
        int D = Integer.parseInt(in[3]);

        while (true) {
            C -= B;
            if (C <= 0) {
                System.out.println("Yes");
                break;
            }

            A -= D;
            if (A <= 0) {
                System.out.println("No");
                break;
            }
        }
    } Scanner s = new Scanner(System.in); s new Scanner(System.in) String[] in = s.nextLine().split(" "); in s.nextLine().split(" ") s.nextLine().split s.nextLine() s.nextLine s " " int A = Integer.parseInt(in[0]); A Integer.parseInt(in[0]) Integer.parseInt Integer in[0] in 0 int B = Integer.parseInt(in[1]); B Integer.parseInt(in[1]) Integer.parseInt Integer in[1] in 1 int C = Integer.parseInt(in[2]); C Integer.parseInt(in[2]) Integer.parseInt Integer in[2] in 2 int D = Integer.parseInt(in[3]); D Integer.parseInt(in[3]) Integer.parseInt Integer in[3] in 3 while (true) {
            C -= B;
            if (C <= 0) {
                System.out.println("Yes");
                break;
            }

            A -= D;
            if (A <= 0) {
                System.out.println("No");
                break;
            }
        } true {
            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 s = new Scanner(System.in);
        String[] in = s.nextLine().split(" ");
        int A = Integer.parseInt(in[0]);
        int B = Integer.parseInt(in[1]);
        int C = Integer.parseInt(in[2]);
        int D = Integer.parseInt(in[3]);

        while (true) {
            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 s = new Scanner(System.in);
        String[] in = s.nextLine().split(" ");
        int A = Integer.parseInt(in[0]);
        int B = Integer.parseInt(in[1]);
        int C = Integer.parseInt(in[2]);
        int D = Integer.parseInt(in[3]);

        while (true) {
            C -= B;
            if (C <= 0) {
                System.out.println("Yes");
                break;
            }

            A -= D;
            if (A <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
} Main
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        String[] in = s.nextLine().split(" ");
        int A = Integer.parseInt(in[0]);
        int B = Integer.parseInt(in[1]);
        int C = Integer.parseInt(in[2]);
        int D = Integer.parseInt(in[3]);

        while (true) {
            C -= B;
            if (C <= 0) {
                System.out.println("Yes");
                break;
            }

            A -= D;
            if (A <= 0) {
                System.out.println("No");
                break;
            }
        }
    }
}