
import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int A = sc.nextInt();

        int B = sc.nextInt();

        int C = sc.nextInt();

        int D = sc.nextInt();

        String flag;
        while (true) {
            C -= B;
            if (C <= 0) {
                flag = "t";
                break;
            }
            A -= D;
            if (A <= 0) {
                flag = "a";
                break;
            }
        }
        if (flag.equals("t")) System.out.println("Yes");
        else System.out.println("No");
    }

} import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int A = sc.nextInt();

        int B = sc.nextInt();

        int C = sc.nextInt();

        int D = sc.nextInt();

        String flag;
        while (true) {
            C -= B;
            if (C <= 0) {
                flag = "t";
                break;
            }
            A -= D;
            if (A <= 0) {
                flag = "a";
                break;
            }
        }
        if (flag.equals("t")) System.out.println("Yes");
        else System.out.println("No");
    }

} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int A = sc.nextInt();

        int B = sc.nextInt();

        int C = sc.nextInt();

        int D = sc.nextInt();

        String flag;
        while (true) {
            C -= B;
            if (C <= 0) {
                flag = "t";
                break;
            }
            A -= D;
            if (A <= 0) {
                flag = "a";
                break;
            }
        }
        if (flag.equals("t")) System.out.println("Yes");
        else System.out.println("No");
    } main {
        Scanner sc = new Scanner(System.in);

        int A = sc.nextInt();

        int B = sc.nextInt();

        int C = sc.nextInt();

        int D = sc.nextInt();

        String flag;
        while (true) {
            C -= B;
            if (C <= 0) {
                flag = "t";
                break;
            }
            A -= D;
            if (A <= 0) {
                flag = "a";
                break;
            }
        }
        if (flag.equals("t")) System.out.println("Yes");
        else System.out.println("No");
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int A = sc.nextInt(); A sc.nextInt() sc.nextInt sc int B = sc.nextInt(); B sc.nextInt() sc.nextInt sc int C = sc.nextInt(); C sc.nextInt() sc.nextInt sc int D = sc.nextInt(); D sc.nextInt() sc.nextInt sc String flag; flag while (true) {
            C -= B;
            if (C <= 0) {
                flag = "t";
                break;
            }
            A -= D;
            if (A <= 0) {
                flag = "a";
                break;
            }
        } true {
            C -= B;
            if (C <= 0) {
                flag = "t";
                break;
            }
            A -= D;
            if (A <= 0) {
                flag = "a";
                break;
            }
        } C -= B C B if (C <= 0) {
                flag = "t";
                break;
            } C <= 0 C 0 {
                flag = "t";
                break;
            } flag = "t" flag "t" break; A -= D A D if (A <= 0) {
                flag = "a";
                break;
            } A <= 0 A 0 {
                flag = "a";
                break;
            } flag = "a" flag "a" break; if (flag.equals("t")) System.out.println("Yes");
        else System.out.println("No"); flag.equals("t") flag.equals flag "t" System.out.println("Yes") System.out.println System.out System System.out "Yes" 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 A = sc.nextInt();

        int B = sc.nextInt();

        int C = sc.nextInt();

        int D = sc.nextInt();

        String flag;
        while (true) {
            C -= B;
            if (C <= 0) {
                flag = "t";
                break;
            }
            A -= D;
            if (A <= 0) {
                flag = "a";
                break;
            }
        }
        if (flag.equals("t")) System.out.println("Yes");
        else System.out.println("No");
    }

} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int A = sc.nextInt();

        int B = sc.nextInt();

        int C = sc.nextInt();

        int D = sc.nextInt();

        String flag;
        while (true) {
            C -= B;
            if (C <= 0) {
                flag = "t";
                break;
            }
            A -= D;
            if (A <= 0) {
                flag = "a";
                break;
            }
        }
        if (flag.equals("t")) System.out.println("Yes");
        else System.out.println("No");
    }

} Main

import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int A = sc.nextInt();

        int B = sc.nextInt();

        int C = sc.nextInt();

        int D = sc.nextInt();

        String flag;
        while (true) {
            C -= B;
            if (C <= 0) {
                flag = "t";
                break;
            }
            A -= D;
            if (A <= 0) {
                flag = "a";
                break;
            }
        }
        if (flag.equals("t")) System.out.println("Yes");
        else System.out.println("No");
    }

}
