Triangles#2400

Triangles

1 second

128 megabytes

Very easy

Misha loved drawing triangles, but he did it in an unusual way. First, he drew an arbitrary triangle. Then, he divided each of its sides into $n$ equal parts and drew lines through the division points, parallel to the sides of the triangle. As a result, a grid of identical triangles was formed.

Input

One integer $n$ ( $0 < n < 2 \cdot 1 0^{9}$ 0 < n < 2 \cdot 10^9).

Output

Print the maximum number of equal triangles.

Examples

Example 1

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0 < n < 2 \cdot 1 0^{9}