def show_board(board):
    """
    Shows the board.

    >>> print(show_board(starting_board()))
     abcdefgh
    8RNBQKBNR8
    7PPPPPPPP7
    6........6
    5........5
    4........4
    3........3
    2pppppppp2
    1rnbqkbnr1
     abcdefgh
    """
    def row_to_str(row):
        return "".join([str(board.get((col,row), ".")) for col in range(1,9)])
    return (" abcdefgh\n" +
            "".join([ (str(row) + row_to_str(row) + str(row) + "\n") for row in range(8,0,-1)]) +
            " abcdefgh")