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A. Filling Shapes

time limit per test

1 secondmemory limit per test

256 megabytesinput

standard inputoutput

standard outputYou 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.

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.

Codeforces (c) Copyright 2010-2019 Mike Mirzayanov

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