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Package for this problem was not updated by the problem writer or Codeforces administration after we’ve upgraded the judging servers. To adjust the time limit constraint, solution execution time will be multiplied by 2. For example, if your solution works for 400 ms on judging servers, then value 800 ms will be displayed and used to determine the verdict.

The following languages are additionally available for the problems from the contest

April Fools Day Contest:

- Secret_171

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B. Star

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputInput

The input contains a single integer *a* (1 ≤ *a* ≤ 18257).

Output

Print a single integer *output* (1 ≤ *output* ≤ 2·10^{9}).

Examples

Input

2

Output

13

Codeforces (c) Copyright 2010-2020 Mike Mirzayanov

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