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A12753. Filling Shapes

编程题 普及/提高-

题目描述

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.

![](/uploads/acgo/image/283776b460623fbc_aecf963f17b7.jpeg) This picture describes when $n = 4$ . The left one is the shape and the right one is $3 \times n$ tiles.

输入格式

The only line contains one integer $n$ ( $1 \le n \le 60$ ) — the length.

输出格式

Print the number of ways to fill.

输入输出样例

输入 #1
4
输出 #1
4
输入 #2
1
输出 #2
0

说明/提示

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.
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