#307. Sum of powers of 2
You get n. Use a loop to find the sum 2⁰ + 2¹ + ... + 2ⁿ.
### Input
One integer n (0 ≤ n ≤ 30).
### Output
The sum.
Examples
Input
8
Output
511
Input
10
Output
2047
💡 You can solve it with Python, JavaScript or blocks. Read the input line by line with input(). Don't print a question (like input("Number: ")). Print exactly what the output asks for, nothing more.