Card houses#5716
Slavik dreams of becoming a performer of an original genre, so he constantly practices manipulating various objects. Lately, he has been dedicating all his free time to building card houses. He has already managed to construct a four-story card house at home, which required cards. During a technology class, Slavik secretly demonstrated his skill to his classmates by building a three-story card house using only cards.
The "creations" of the future artist are captured in the photos below:
Now Slavik is interested in a mathematical question: how many cards are needed to build a card house of stories?
He asks for your help, as mathematics is not his strongest subject.
One non-negative integer n~(n \le 10^8) — the number of stories in the card house to be built.
Print the number of cards required to build a card house with stories.
Example 1
Example 2