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Problems

Gardener-painter

Gardener-painter

Time limit 1 second
Memory limit 64 MiB

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