Memory cards

def play_round(cards, i_1, i_2, round_num):
    if i_1 == i_2 or i_1 not in range(len(cards)) or i_2 not in range(len(cards)):
        print(f"Invalid input! Adding additional elements to the board")
        card = f"-{round_num}a"
        middle = len(cards) // 2
        cards.insert(middle, card)
        cards.insert(middle + 1, card)
        return cards

    if cards[index_1] == cards[index_2]:
        element = cards[index_1]
        print(f"Congrats! You have found matching elements - {element}!")
        cards.remove(element)
        cards.remove(element)
        return cards

    print(f"Try again!")
    return cards



memory_cards = input().split()
command = input()
counter = 0

while not command == 'end':
    index_1, index_2 = list(map(int, command.split()))
    counter += 1
    memory_cards = play_round(memory_cards, index_1, index_2, counter)
    if len(memory_cards) == 0:
        print(f"You have won in {counter} turns!")
        break
    command = input()

if len(memory_cards) > 0:
    print(f"Sorry you lose :(")
    print(' '.join(memory_cards))