Nested_ContinentsCities

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Lab2
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<string, Dictionary<string, List<string>>> continentsData = new Dictionary<string, Dictionary<string, List<string>>>();
            int counter = int.Parse(Console.ReadLine());

            for (int i = 0; i < counter; i++)
            {
                string[] inputCounter = Console.ReadLine().Split(' ');
                string continent = inputCounter[0];
                string country = inputCounter[1];
                string cities = inputCounter[2];

                if (!continentsData.ContainsKey(continent))
                {
                    continentsData.Add(continent, new Dictionary<string, List<string>>());
                }
                if (!continentsData[continent].ContainsKey(country))
                {
                    continentsData[continent][country] = new List<string>();
                }
                continentsData[continent][country].Add(cities);
            }
            foreach (KeyValuePair<string, Dictionary<string, List<string>>> item in continentsData)
            {
                string continentName = item.Key;
                Console.WriteLine($"{continentName}:");
                Dictionary<string, List<string>> countriescities = item.Value;
                foreach (var data in countriescities)
                {
                    string country = data.Key;

                    Console.WriteLine($"  {country} -> {string.Join(", ", data.Value)}");
                }

            }
        }
    }
}