Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.
You have a given integer $$$n$$$. Find the number of ways to fill all $$$3 \times n$$$ tiles with the shape described in the picture below. Upon filling, no empty spaces are allowed. Shapes cannot overlap.
This picture describes when $$$n = 4$$$. The left one is the shape and the right one is $$$3 \times n$$$ tiles.
Input
The only line contains one integer $$$n$$$ ($$$1 \le n \le 60$$$) — the length.
Output
Print the number of ways to fill.
Examples
Input
4
Output
4
Input
1
Output
0
Note
In the first example, there are $$$4$$$ possible cases of filling.
In the second example, you cannot fill the shapes in $$$3 \times 1$$$ tiles.