def get_seat_id(seat_str: str) -> int:
    """Parse the seat specification string, and return the seat ID

    :param seat_str: Seat specification string
    :return: Seat ID
    """
    row = 0
    col = 0
    for i, char in enumerate(seat_str[:7]):
        row += (char == 'B') * 2 ** (6 - i)

    for i, char in enumerate(seat_str[7:]):
        col += (char == 'R') * 2 ** (2 - i)

    return row * 8 + col