First Bad Version

Versions are numbered 1 to n. Every version from some version b onward is bad, and all earlier versions are good, so the `is bad` property is monotonic. You are told n and b. Using the fewest checks (binary search over the monotonic boolean sequence), find and print the first bad version. Input format: - One line: n b

1 <= b <= n <= 2 * 10^9

5 4

4

1 1

1