Bacteria Growth Simulation

You are given a non-negative integer n representing the number of generations. A single bacterium starts reproducing from generation 0, and with each new generation, every existing bacterium splits into two. The total number of bacteria at generation n is given by the formula:

$$2^{(n+1)} - 1$$

Your task is to compute and output the total number of bacteria after n generations.

inputFormat

Input consists of a single integer n (0 ≤ n), representing the number of generations.

outputFormat

Output the total number of bacteria after n generations.## sample

0

1