#851. Digit sum in base 2
You get n. Write n in base 2 and find the sum of its digits with a function `digit_sum(n, base)`.
### Input
One integer n (0 ≤ n ≤ 10⁹).
### Output
A number.
Examples
Input
911088603
Output
18
Input
762808419
Output
16
💡 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.