def list_reads_number(config):
    """
    return the number of different reads from config

    :params config
    :return:
    """
    read_number = 0
    for adaptator in config:
        if not adaptator == 'conditions':
            if int(config[adaptator]['coords']['reads']) > read_number:
                read_number = int(config[adaptator]['coords']['reads'])
    return read_number + 1
