memory_game

def try_match(index1, index2, list_of_elements):
    first_element = ''
    second_element = ''
    for index, element in enumerate(list_of_elements):
        if index == index1:
            first_element = element
        elif index == index2:
            second_element = element
    if first_element == second_element:
        list_of_elements.remove(first_element)
        list_of_elements.remove(second_element)
        print(f"Congrats! You have found matching elements - {first_element}!")
    else:
        print(f"Try again!")


def invalid_index(moves, list_of_elements):
    first_half_of_list = len(list_of_elements) // 2
    for index, element in enumerate(list_of_elements):
        if index == first_half_of_list:
            list_of_elements.insert(index, f"-{moves}a")
            list_of_elements.insert(index + 1, f"-{moves}a")
            print(f"Invalid input! Adding additional elements to the board")


def game_progress(list_of_elements):
    moves_counter = 0
    player_won = False
    while True:
        command = input()
        if command == 'end':
            break
        moves_counter += 1
        first_index, second_index = map(int, command.split())

        if first_index < 0 or first_index > len(sequence_of_elements) or second_index < 0 or second_index > len(
                sequence_of_elements) or first_index == second_index:
            invalid_index(moves_counter, sequence_of_elements)

        else:
            try_match(first_index, second_index, sequence_of_elements)

        if len(sequence_of_elements) == 0:
            player_won = True
            break
    if player_won:
        print(f"You have won in {moves_counter} turns!")
    else:
        print(f"Sorry you lose :(\n{' '.join(list_of_elements)}")


sequence_of_elements = input().split()
game_progress(sequence_of_elements)