GUESS005 - Guess the task V

no tags 

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...................................................n vertex....................................................................................................

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.....................................................................................3,14.......................................................................

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...................................................................................................................r..............................................

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Example

Input:
10 6
Output:
60.0


Added by:Piotr KÄ…kol
Date:2010-04-06
Time limit:3s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All