Binary form of a number

Problem

Write a recursive function that returns the binary form of a non-negative integer as text, without using bin or format. Print it.

Example

Input

Output

1010 in binary.

Try the problem first. Open one hint at a time.

Hint 1

The last bit is n % 2 and the rest is n // 2.

Hint 2

Handle n < 2 as the base case, returning str(n).

Write your Python code, run it on the examples and submit it to hidden tests.