# Match’s model

Hard

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

Professor Samodelkin decided to make a three-dimensional model of cubes from matches 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 smallest number of matches needed by Samodilkin to build a model of $n$ cubes.

All numbers in this problem do not exceed $2⋅10_{9}$.

## Input

One number $n$ is the number of cubes.

## Output

The number of matches needed.

## Examples

Input #1

Answer #1

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