Problems

# Gardener-painter

# Gardener-painter

Gardener has to paint trees after planting. He has paint of three colour: white, blue and orange.

How many ways he can paint of N trees, if not any two the same colours can be side by side?

## Input data

The quantity of trees is N(1 ≤ N ≤ 50).

## Output data

The quantity of ways of paint.

## Examples

Input example #1

3

Output example #1

12