using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Въведи брой ученици");

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

        double max = double.MinValue;

        double min = double.MaxValue;

        double sum=0;

        int excellentCount=0;

        string failedStudents = "";

        double[] grades = new double[N];

        for (int i=0; i<N ;i++)

        {

            Console.WriteLine("Vuvedi ocenki");

            grades[i]= double.Parse(Console.ReadLine());

            sum +=grades[i];

            if (grades[i] >max)

            {

                max= grades[i];

            }

            if (grades[i] <min)

            {

                min = grades[i];

            }

             if (grades[i] >= 5.50)

           {

               excellentCount++;

           }

           if (grades[i] < 3.00)

           {

               failedStudents += (i + 1) + " ";

           }

       }

       double average = sum / N;

       Console.WriteLine();

       Console.WriteLine("Sreden uspeh: " + average.ToString("F2"));

       Console.WriteLine("Nai-visok ocenka: " + max);

       Console.WriteLine("Nai-niska ocenka: " + min);

       Console.WriteLine("Broi otlichnici: " + excellentCount);

       Console.WriteLine("Nomera na uchenici s dvoiki: " + (failedStudents == "" ? "няма" : failedStudents));

        }

    }

​