using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(String.Join(",",twodigi(10)));

    }

    public static int[] twodigi(int number)

    {

        Random random = new Random();    

        int[] a = new int[number];

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

        {         

            a[i] = random.Next(10, 100);

        }

​

          return a.GroupBy(v => v).Select(x=> x.Key + x.Count()).ToArray();

    }

}