A12753. Filling Shapes
编程题
普及/提高-
知识点
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.
 This picture describes when $n = 4$ . The left one is the shape and the right one is $3 \times n$ tiles.
 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.
In the second example, you cannot fill the shapes in $3 \times 1$ tiles.