CompanyUsers*

using System;
using System.Collections.Generic;
using System.Linq;

namespace CompanyUsers
{
    class Program
    {
        static void Main(string[] args)
        {
            var companiesAndEmployeesDictionary = new SortedDictionary<string, List<string>>();
            string command = string.Empty;

            while ((command = Console.ReadLine()) != "End")
            {
                string [] commandArray = command.Split(" -> ");
                string company = commandArray[0];
                string id = commandArray[1];

                if (companiesAndEmployeesDictionary.ContainsKey(company) == false)
                {
                    companiesAndEmployeesDictionary[company] = new List<string>();
                    companiesAndEmployeesDictionary[company].Add(id);
                }

                else
                {
                    if (companiesAndEmployeesDictionary[company].Contains(id) == false)
                    {
                        companiesAndEmployeesDictionary[company].Add(id);
                    }
                }
            }

            foreach (var kvp in companiesAndEmployeesDictionary)
            {
                string company = kvp.Key;
                List<string>listIds = kvp.Value;
                Console.WriteLine($"{company}");
                foreach (var id in listIds)
                {
                    Console.WriteLine($"-- {id}");
                }
            }
        }
      }
    }