dictionary = {}

count = int(input())

for _ in range(count):
    line = input()
    line_split = line.split()
    command = line_split[0]
    name = line_split[1]

    if command == "register":
        plate_number = line_split[2]
        if name in dictionary:
            print(f"ERROR: already registered with plate number {dictionary[name]}")
        else:
            dictionary[name] = plate_number
            print(f"{name} registered {plate_number} successfully")

    else:
        if name not in dictionary:
            print(f"ERROR: user {name} not found")

        else:
            dictionary.pop(name)
            print(f"{name} unregistered successfully")

for name, plate_number in dictionary.items():
    print(f"{name} => {plate_number}")