PhoneBook

namespace PhoneBook
{
    using System;
    using System.Collections.Generic;

    public class Startup
    {
        public static void Main()
        {
            string input;
            Dictionary<string, string> phoneBook = new Dictionary<string, string>();
            while ((input = Console.ReadLine()) != "END")
            {
                string[] inputArgs = input
                    .Split(new[] {' '}, StringSplitOptions.RemoveEmptyEntries);

                if (inputArgs.Length == 3)
                {
                    phoneBook[inputArgs[1]] = inputArgs[2];
                    continue;
                }
                Console.WriteLine(phoneBook.ContainsKey(inputArgs[1]) ? $"{inputArgs[1]} -> {phoneBook[inputArgs[1]]}" : $"Contact {inputArgs[1]} does not exist.");
            }
        }
    }
}