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Problems

Bone for the Sharik

Bone for the Sharik

Time limit 1 second
Memory limit 64 MiB

— 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 (1N100).

Output data

Single number - the required amount of seed.

Examples

Input example #1
3
Output example #1
511