#!/usr/bin/env python3

from sys import stdin, stdout, argv
from xml.etree.ElementTree import ElementTree
import xml


tree = ElementTree()
#xml.etree.ElementTree.register_namespace("","http://www.w3.org/2005/Atom")
tree.parse(stdin)

if argv[1] == '--whitelist':
    whitelist=True
    keywordID = argv[2:]
else:
    whitelist=False
    keywordID = argv[1:]
root = tree.getroot()

for channel in tree.findall('channel'):
    for node in tree.findall('.//item'):
        ch = node.find('title')
        if ch is not None:
            node_matched = False
            for keyword in keywordID:
                if ch.text.find(keyword) != -1:
                    node_matched = True
                    break
            if node_matched ^ whitelist:
                channel.remove(node)
tree.write(stdout, encoding='unicode')