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Description
The input contains a single integer a (1 ≤ a ≤ 18257).
Print a single integer output (1 ≤ output ≤ 2·109).
Input
The input contains a single integer a (1 ≤ a ≤ 18257).
Output
Print a single integer output (1 ≤ output ≤ 2·109).
Samples
2
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