Sets & Dictionaries Advanced - 03. Periodic Table

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace Advanced
{
    class Program
    {
        static void Main(string[] args)
        {
            var periodicTable = new SortedSet<string>();

            int number = int.Parse(Console.ReadLine());

            for (int i = 0; i < number; i++)
            {
                var elements = Console.ReadLine().Split();

                foreach (var element in elements)
                {
                    periodicTable.Add(element);
                }
            }

            Console.WriteLine(string.Join(" ", periodicTable));
        }
    }
}