import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int A = scan.nextInt();
        int B = scan.nextInt();
        int C = scan.nextInt();
        int D = scan.nextInt();

        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.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int A = scan.nextInt();
        int B = scan.nextInt();
        int C = scan.nextInt();
        int D = scan.nextInt();

        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 scan = new Scanner(System.in);
        int A = scan.nextInt();
        int B = scan.nextInt();
        int C = scan.nextInt();
        int D = scan.nextInt();

        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 scan = new Scanner(System.in);
        int A = scan.nextInt();
        int B = scan.nextInt();
        int C = scan.nextInt();
        int D = scan.nextInt();

        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 scan = new Scanner(System.in); scan new Scanner(System.in) int A = scan.nextInt(); A scan.nextInt() scan.nextInt scan int B = scan.nextInt(); B scan.nextInt() scan.nextInt scan int C = scan.nextInt(); C scan.nextInt() scan.nextInt scan int D = scan.nextInt(); D scan.nextInt() scan.nextInt scan 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 scan = new Scanner(System.in);
        int A = scan.nextInt();
        int B = scan.nextInt();
        int C = scan.nextInt();
        int D = scan.nextInt();

        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 scan = new Scanner(System.in);
        int A = scan.nextInt();
        int B = scan.nextInt();
        int C = scan.nextInt();
        int D = scan.nextInt();

        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.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int A = scan.nextInt();
        int B = scan.nextInt();
        int C = scan.nextInt();
        int D = scan.nextInt();

        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;
            }
        }
    }
}