using System.Collections.Generic;
public static void Main()
List<Tuple<int, int>> list = new List<Tuple<int, int>>()
new Tuple<int, int>(1,12),
new Tuple<int, int>(1,2),
new Tuple<int, int>(1,18),
new Tuple<int, int>(1,12),
new Tuple<int, int>(2,12),
foreach(var item in list.Distinct().ToList())