using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Please enter quiz count.");

        string enteredValue = Console.ReadLine();

​

        int quizCount = 0;

        if (int.TryParse(enteredValue, out quizCount))

        {

            double sum = 0;

​

            if (quizCount > 0)

            {

                for (int i = 1; i <= quizCount; i++)

                {

                    Console.WriteLine("Please enter quiz mark.");

                    string enteredmarkValue = Console.ReadLine();

​

                    double quizValue = 0;

                   if (double.TryParse(enteredmarkValue, out quizValue))

                    {

                       if   (quizValue > 0)  

                       {

                    sum = sum + quizValue;

                         }

                       else        

                        {  

                           Console.WriteLine("Quiz mark can be only positive" ); 

                         }  

                     }

                     else

                     {

                         Console.WriteLine("Quiz mark can be only number" );

                     }

                   }

​

                double average = sum / quizCount;

​

                Console.WriteLine("Our average is " + average);

            }

            else    

                {

                Console.WriteLine("Count can't be negative!!!");

                } 

            }   

        else

           {

            Console.WriteLine("You should enter int!");

           }    

    }

}