Squares - 2#146

Squares - 2

1 second

128 megabytes

Very easy

Starting with a white square, perform the following operation $n$ times: at each step, take one of the smallest remaining white squares, divide it into $4$ equal squares, and paint $2$ of them black. Given $n$ , calculate what percentage of the total area is black after all operations.

Input

The input contains one integer $n$ ( $1 \leq n \leq 100$ 1 \leq n \leq 100).

Output

Print the percentage of the area that is black, rounded to $5$ decimal places.

Examples

Example 1

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1 \leq n \leq 100