import java.util.Scanner;

public class Main {
    private static final int MOD = 1_000_000_007;
    private static final String YES = "Yes";
    private static final String NO = "No";

    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();

        System.out.println(solve(A, B, C, D) ? YES : NO);
    }

    private static boolean solve(int A, int B, int C, int D) {
        while (true) {
            C -= B;
            if (C <= 0) return true;

            A -= D;
            if (A <= 0) return false;
        }
    }
} import java.util.Scanner; Scanner java.util public class Main {
    private static final int MOD = 1_000_000_007;
    private static final String YES = "Yes";
    private static final String NO = "No";

    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();

        System.out.println(solve(A, B, C, D) ? YES : NO);
    }

    private static boolean solve(int A, int B, int C, int D) {
        while (true) {
            C -= B;
            if (C <= 0) return true;

            A -= D;
            if (A <= 0) return false;
        }
    }
} Main private static final int MOD = 1_000_000_007; MOD 1_000_000_007 private static final String YES = "Yes"; YES "Yes" private static final String NO = "No"; NO "No" 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();

        System.out.println(solve(A, B, C, D) ? YES : NO);
    } main {
        Scanner sc = new Scanner(System.in);

        int A = sc.nextInt();
        int B = sc.nextInt();
        int C = sc.nextInt();
        int D = sc.nextInt();

        System.out.println(solve(A, B, C, D) ? YES : 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 System.out.println(solve(A, B, C, D) ? YES : NO) System.out.println System.out System System.out solve(A, B, C, D) ? YES : NO solve(A, B, C, D) solve A B C D YES NO String[] args args private static boolean solve(int A, int B, int C, int D) {
        while (true) {
            C -= B;
            if (C <= 0) return true;

            A -= D;
            if (A <= 0) return false;
        }
    } solve {
        while (true) {
            C -= B;
            if (C <= 0) return true;

            A -= D;
            if (A <= 0) return false;
        }
    } while (true) {
            C -= B;
            if (C <= 0) return true;

            A -= D;
            if (A <= 0) return false;
        } true {
            C -= B;
            if (C <= 0) return true;

            A -= D;
            if (A <= 0) return false;
        } C -= B C B if (C <= 0) return true; C <= 0 C 0 return true; true A -= D A D if (A <= 0) return false; A <= 0 A 0 return false; false int A A int B B int C C int D D public class Main {
    private static final int MOD = 1_000_000_007;
    private static final String YES = "Yes";
    private static final String NO = "No";

    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();

        System.out.println(solve(A, B, C, D) ? YES : NO);
    }

    private static boolean solve(int A, int B, int C, int D) {
        while (true) {
            C -= B;
            if (C <= 0) return true;

            A -= D;
            if (A <= 0) return false;
        }
    }
} public class Main {
    private static final int MOD = 1_000_000_007;
    private static final String YES = "Yes";
    private static final String NO = "No";

    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();

        System.out.println(solve(A, B, C, D) ? YES : NO);
    }

    private static boolean solve(int A, int B, int C, int D) {
        while (true) {
            C -= B;
            if (C <= 0) return true;

            A -= D;
            if (A <= 0) return false;
        }
    }
} Main
import java.util.Scanner;

public class Main {
    private static final int MOD = 1_000_000_007;
    private static final String YES = "Yes";
    private static final String NO = "No";

    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();

        System.out.println(solve(A, B, C, D) ? YES : NO);
    }

    private static boolean solve(int A, int B, int C, int D) {
        while (true) {
            C -= B;
            if (C <= 0) return true;

            A -= D;
            if (A <= 0) return false;
        }
    }
}