Filling Shapes

You have a given integer n. Find the number of ways to fill all 3 × 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 × n tiles.

Input

The only line contains one integer n (1 ≤ n ≤ 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 × 1 tiles.

inputFormat

Input

The only line contains one integer n (1 ≤ n ≤ 60) — the length.

outputFormat

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 × 1 tiles.

样例

1

0