CF932E Team Work

Description

You have a team of $ N $ people. For a particular task, you can pick any non-empty subset of people. The cost of having $ x $ people for the task is $ x^{k} $ . Output the sum of costs over all non-empty subsets of people.

Input Format

N/A

Output Format

N/A

Explanation/Hint

In the first example, there is only one non-empty subset $ {1} $ with cost $ 1^{1}=1 $ . In the second example, there are seven non-empty subsets. \- $ {1} $ with cost $ 1^{2}=1 $ \- $ {2} $ with cost $ 1^{2}=1 $ \- $ {1,2} $ with cost $ 2^{2}=4 $ \- $ {3} $ with cost $ 1^{2}=1 $ \- $ {1,3} $ with cost $ 2^{2}=4 $ \- $ {2,3} $ with cost $ 2^{2}=4 $ \- $ {1,2,3} $ with cost $ 3^{2}=9 $ The total cost is $ 1+1+4+1+4+4+9=24 $ .