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

The quantity of trees is `N`

(`1 ≤ N ≤ 50`

).

#### Output

The quantity of ways of paint.

Input example #1

3

Output example #1

12