Save our Souls

The 3008-th year. People at last finally have advanced in study of the theory thorsion fields and have realized, that each man has a certain essence, which they have named as a print of individuality, and in slang already during 10 thousand years named as soul. The soul of the man carries the information that this man is this man, instead of any another. Besides the scientists have understood, that in the June of the 3008-th year all souls will leave the bodies and will disappear. That it to not allow special device named The Catcher of Souls immediately was designed. But its start and works will need a lot of energy, which consumption at it linely depends on that volume of the information, which is carried by the soul. Therefore scientists have decided at once to determine, how many minimally information can be carried in itself by the soul of one man, were guided only by that known fact, that on the Earth lives N of the people.

The entrance data
The file input.txt contains a sole integer N (0 < =N < =10¹⁰⁰⁰).

The target data
The file output.txt should contain a sole integer - minimum quantity of the information in bits, which can be carried in itself by the soul of the man.

Example
input.txt
10
output.txt
4