For this task, we have logs from various web sites. These logs contain information about user http and https requests. To analyse this data we need to parse and collect the information contained in these logs.

A log file is a text file, where each request is represented as a string. The strings are separated by a newline "\n". Requests contain a timestamp, username and URL. These fields are separated by ";;" .
Timestamps are represented in the following format:
YYYY-MM-DD-hh-mm-ss , where YYYY-MM-DD is the date, hh-mm-ss is the time.
Usernames contain only letters, digits and an underscore.
A URL is given in the normalized form (for example: http://checkio.org).
All fields are case-insensitive and must be converted in the lowercase.

You should collect information about user sessions from the given logs. A session is a sequence of the user requests at the same site (second-level domain), where each request is no more than 30 minutes older than the previous request from that user at the same site. We compare URL by second-level domain name, so admin.checkio.org and...

This log contains 4 sessions. The first three requests (1-3) are created by "Name" ("name") at the same site, checkio.org with no more than 30 minutes between "neighbour" requests. The second session contains two requests (4, 6) from "Name" at checkio.org (more than 30 minutes from 01:31:00 request). The next is the request (5) at example.com . The last session is the request (7) from "user2" at checkio.org .

The results should contain information about sessions in the next format:
username;;site;;duration;;quantity_of_requests
where each string is a session.

• username is a username from logs.
• site is a second-level domain.
• duration is a time from first to last requests in seconds. The seconds are calculated inclusively. If there's only one request in the session, then it has 1 second duration. For example: two requests at 00:00:00 and 00:00:02 -- 3 seconds duration.
• quantity_of_requests is a quantity of request in the session.

name;;checkio.org;;661;;2
name;;checkio.org;;1861;;3
name;;example.com;;1;;1
user2;;checkio.org;;1;;1

Input: A log text, a multilines string (unicode).

Output: Sessions data, a multilines string.

checkio("""2013-01-01-01-00-00;;Name;;http://checkio.org/task
2013-01-01-01-02-00;;name;;http://checkio.org/task2
2013-01-01-01-31-00;;Name;;https://admin.checkio.org
2013-01-01-03-00-00;;Name;;http://www.checkio.org/profile
2013-01-01-03-00-01;;Name;;http://example.com
2013-02-03-04-00-00;;user2;;http://checkio.org/task
2013-01-01-03-11-00;;Name;;http://checkio.org/task""") ==
"""name;;checkio.org;;661;;2
name;;checkio.org;;1861;;3
name;;example.com;;1;;1
user2;;checkio.org;;1;;1"""

How it is used: This concept comes in handy when you need to gather aggregated data from the collected log file. This will help you to get information about user session for the various sites. You can improve your code here for more complex cases.