using System;
using System.Collections.Generic;
using System.Linq;
public class Program
{
public static void Main()
var items = new int[]
3, 4, 2, 1, 5,
};
var hasSet = new HashSet<int>(items);
Console.WriteLine("Items count: {0}", items.Count());
Console.WriteLine("HashSet count: {0}", hasSet.Count());
foreach(var hash in hasSet)
Console.WriteLine(hash);
}