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