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**Task** | Statistics

Time limit: | 1.00 s | Memory limit: | 512 MB |

Each square of an $8 \times 8$ chessboard has a robot. Each robot independently moves $k$ steps, and there can be many robots on the same square.

On each turn, a robot moves one step left, right, up or down, but not outside the board. It randomly chooses a direction among those where it can move.

Your task is to calculate the expected number of

The only input line has an integer $k$.

Print the expected number of empty squares rounded to six decimal places.

- $1 \le k \le 100$

Input:

`10`

Output:

`23.120740`