WHY 31 DAY IN JULY AND AUGUST?

After himself - the Emperor Julius Caesar named the month of July where it is still 31 days,
The Emperor Augustus, following the example of his predecessor, too, wished to have a "personal" month - before the calendar was the month of August. It was named by Augustus in honor of Emperor Augustus . The Emperor is not pleased, in the month of July 31 days and August only 30. I'm worse than Emperor Julius Caesar decided to subtract one day from the already "offended" February (it was then only 29 days) and added it to August.
Now, thanks to these privileges of the Emperor Octavian Augustus in February 28 days , but in the two months to 31 day .