Sum of Pascal's Triangle Row

Given an integer n that represents the row number (1-indexed) in Pascal's Triangle, compute the sum of the elements in that row. Recall from combinatorial properties that the sum of the elements of the nth row in Pascal's Triangle is given by (2^{n-1}). Your task is to read an integer from standard input and output the corresponding sum.

inputFormat

The input consists of a single integer n (1 ≤ n). This integer represents the row number in Pascal's Triangle (1-indexed).

outputFormat

Output a single integer which is the sum of the elements in the nth row of Pascal's Triangle.## sample

1

1