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

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            int number = int.Parse(Console.ReadLine());


            var students = new Dictionary<string, string>();

            for (int i = 0; i < number; i++)
            {
                string[] input = Console.ReadLine().Split().ToArray();

                string todo = input[0];


                if (todo == "register")
                {
                    string licensenumber = input[2];

                    if (students.ContainsValue(licensenumber))
                    {
                        Console.WriteLine($"ERROR: already registered with plate number {licensenumber}");
                    }
                    else
                    {
                        string student = input[1];
                        students.Add(student, licensenumber);
                        Console.WriteLine($"{student} registered {licensenumber} successfully");
                    }

                }
                else
                {
                    string student = input[1];
                    if (!students.ContainsKey(student))
                    {
                        Console.WriteLine($"ERROR: user {student} not found");
                    }
                    else
                    {
                        students.Remove(student);
                        Console.WriteLine($"{student} unregistered successfully");
                    }
                }
            }
            foreach (var item in students)
            {
                Console.WriteLine($"{item.Key} => {item.Value}");
            }
        }
    }
}