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.

见题面 Input 部分

见题面 Output 部分

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.