using System;

public class Program

{

    static int[] Nhapmang()

        {

            int[] A;

            Console.WriteLine("Nhap so phan tu:");

            int N = int.Parse(Console.ReadLine());

            A = new int[N];

            for (int i = 0; i < A.Length; i++)

            {

                Console.WriteLine($"Nhap A[{i}]");

                A[i] = int.Parse(Console.ReadLine());

            }

            return A;

        }

        static bool Languyento(int n)

        {

            if (n < 2)

                return false;

            for (int i = 2; i <= Math.Sqrt(n); i++)

            {

                if (n % i == 0)

                    return false;

            }

            return true;

        }

        static void Xuatnguyento(int[] A)

        {

            for (int i = 0; i < A.Length; i++)

            {

                if (Languyento(A[i]))

                {

                    Console.Write($"{A[i]} ");

                }

            }

        }

        static void TinhTBC(int[] A)

        {

            double TBC;

            int S = 0;

            int n = 0;

            for (int i = 0; i < A.Length; i++)

            {

                if (Languyento(A[i]))

                {

                    S+=A[i];

                    n++;

                }

            }

            if (n==0)

            {

                Console.WriteLine("TBC=0");

            }

            else

            {

                TBC = (1.0) * S / n;

                Console.WriteLine($"TBC= {TBC}");

            }

        }

​

        static void Main(string[] args)

        {

            int[] A = Nhapmang();

            Console.Write("Cac so nguyen to trong mang: ");

            Xuatnguyento(A);

            TinhTBC(A);

        }

}