Loading repovive.com/contests/11/problems/A
There is a notebook with pages numbered from to from left to right.
On each day, exactly one remaining page is read. The page must be one of the two ends of the remaining notebook, that is, either the leftmost remaining page or the rightmost remaining page.
For each test case, determine whether it is possible that page is read exactly on day .
The order of reading pages can be chosen arbitrarily, as long as the rule above is followed.
On the first day, only pages and can be read, so page cannot be read.
For example, pages and can be read first, then page is at an end on day .
Page can be read first, then page becomes the right end on day .
We can prove that after 3 days, page cannot be at an end of unread pages.