Problems
Triangles
Triangles
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