using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        var tup = System.ValueTuple.Create<int, int>(123, 1);

        Console.WriteLine(tup);

        Console.WriteLine(tup.Item1);

        Console.WriteLine(tup.Item2);

        tup.Item1 = 456;

        tup.Item2 = 9;

        Console.WriteLine(tup);

        Console.WriteLine(tup.Item1);

        Console.WriteLine(tup.Item2);

        var d = new Dictionary<ValueTuple<int,int>, int>();

        d.Add(tup, 3);

        if (d.ContainsKey(tup))

            Console.WriteLine(d[tup]);

    }

}