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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
inputCopy
4
outputCopy
4
inputCopy
1
outputCopy
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