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