Problems
Bone for the Sharik
Bone for the Sharik
— Pechkin you will ever think?
— Why do I think? Let your Burenka thinks - her head is big ...
— Matroskin, what are you out there think?
— Why, I can not calculate how much you owe Sharik seed yield ... You had promised him a reward royally: the first cell of a chessboard the size N x N single bone, the second - two - the third four, and so on, so e. for each next cell twice. So I think what you have to seed Sharik bring ...
Help Matroskin count how many seeds should bring Pechkin.
Прослухати
Читати фонетично
Input data
One number - the size of the chessboard N (1 ≤ N ≤ 100).
Output data
Single number - the required amount of seed.
Examples
Input example #1
3
Output example #1
511