def get_blk_string(block):
    """
    Format the given block id to string

    :param block: memory block id or block string.
    :type string: like 198 or memory198
    :return: returns string memory198 if id 198 is given
    :rtype: string
    """
    if not block.startswith('memory'):
        return 'memory%s' % block
    return block
