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Problems

Triangles

Triangles

Time limit 1 second
Memory limit 128 MiB

Mike likes to draw triangles, but he does it in an unusual way. First he draws an arbitrary triangle, then divides each side into n equal parts and draws through the partition points the lines parallel to sides of triangle. As a result he gets a number of triangles equal to each other. Help Mike to find the maximum number of identical triangles in his final picture.

Input data

One integer n~(0 < n < 2 \cdot 10^9).

Output data

The maximum number of triangles equal to each other.

Examples

Input example #1
2
Output example #1
4