using System;
using System.Collections.Generic;
using System.Linq;

public class Test
{
	public List<int> MyList { get; set; }
	
	
	public static void Main()
	{
		Test t = new Test();
		t.MyList = new List<int>();
		
		t.MyList.Add(-1);
		t.MyList.Add(0);
		t.MyList.Add(1);
		t.MyList.Add(2);
		
		int siteNumbers = t.MyList.Where(i => i != -1)
                   .Select(x => x)
                   .Distinct()
                   .Count();
                   
        Console.WriteLine(siteNumbers);
	}
}