Bacteria Cells Generation

In this problem, you are given an integer n representing the number of generations. The bacteria grow in an interesting way: they double their number at each odd generation and remain the same at every even generation.

The final number of bacteria cells after n generations is given by the formula:

$$2^{\lceil n/2 \rceil}$$

For example, when n = 5, the number of cells is $$2^{\lceil 5/2 \rceil} = 2^3 = 8$$.

Your task is to compute this number for a given generation n.

inputFormat

The input consists of a single integer n read from standard input, representing the number of generations.

Constraints: 1 ≤ n ≤ 100000.

outputFormat

Output a single integer, which is the number of bacteria cells after n generations. The result is computed as

$$2^{\lceil n/2 \rceil}$$

and should be printed to standard output.

## sample

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