Match’s model#3

Match’s model

1 second

128 megabytes

Medium

Kleptyk decided to create a three-dimensional model of cubes using matches for the edges of the cubes. The length of the edge of each cube is equal to one match. He used $28$ matches to build a model of three cubes.

What is the minimum number of matches Kleptyk needs to build a model of $n$ cubes? The cubes must be arranged in the most optimal way.

All numbers in this problem do not exceed $2 \cdot 1 0^{9}$ 2 \cdot 10^9.

Input

The input contains one number $n$ — the number of cubes in the model.

Output

Print the minimum number of matches required to build the model of $n$ cubes.

Examples

Example 1

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2 \cdot 1 0^{9}