[C# Advanced Exam] Population Counter

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

class PopulationCounter
{
    private static void Main()
    {
        Dictionary<string, Dictionary<string, long>> countries = new Dictionary<string, Dictionary<string, long>>();

        while (true)
        {
            string[] input = Console.ReadLine().Split(new char[] { '|' });

            if (input[0] == "report")
                break;

            string town = input[0];
            string country = input[1];
            int population = int.Parse(input[2]);

            if (!countries.ContainsKey(country))
            {
                countries.Add(country, new Dictionary<string, long>());
            }

            countries[country].Add(town, population);
        }
        var sortedCountries =
            countries.OrderByDescending(x => x.Value.Values.Sum());

        foreach (var country in sortedCountries)
        {
            Console.Write("{0} ", country.Key);
            Console.WriteLine("(total population: {0})", country.Value.Values.Sum());

            var sortedTowns = from entry in country.Value orderby entry.Value descending select entry;

            foreach (var town in sortedTowns)
            {
                Console.WriteLine("=>{0}: {1}", town.Key, town.Value);
            }
        }
    }
}