n-th Hexagonal Number

Given a positive integer n, compute the n-th hexagonal number. The hexagonal numbers are defined by the formula:

\(H(n) = n(2n - 1)\)

For example, when n = 1, the hexagonal number is 1; when n = 2, it is 6; when n = 3, it is 15; and so on. Your task is to calculate the n-th hexagonal number and output it as a single integer.

inputFormat

The input consists of a single integer n (1 ≤ n ≤ 10^9) provided via standard input (stdin).

outputFormat

Output the n-th hexagonal number as a single integer to standard output (stdout).## sample

1

1