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문제

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.

입력

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

출력

Print the number of ways to fill.

예제 입력 1

4

예제 출력 1

4

예제 입력 2

1

예제 출력 2

0

노트

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.

출처

Contest > Codeforces > Codeforces Round 566 (Div. 2) A번