Problem F1

Statement
Copy Copied
Description:
This is an interactive problem.

This is an easy version of the problem. The difference from the hard version is that in the easy version $$$t=1$$$ and the number of queries is limited to $$$20$$$.

Polycarp is playing a computer game. In this game, an array consisting of zeros and ones is hidden. Polycarp wins if he guesses the position of the $$$k$$$-th zero from the left $$$t$$$ times.

Polycarp can make no more than $$$20$$$ requests of the following type:

- ? $$$l$$$ $$$r$$$ — find out the sum of all elements in positions from $$$l$$$ to $$$r$$$ ($$$1 \le l \le r \le n$$$) inclusive.

In this (easy version) of the problem, this paragraph doesn't really make sense since $$$t=1$$$ always. To make the game more interesting, each guessed zero turns into one and the game continues on the changed array. More formally, if the position of the $$$k$$$-th zero was $$$x$$$, then after Polycarp guesses this position, the $$$x$$$-th element of the array will be replaced from $$$0$$$ to $$$1$$$. Of course, this feature affects something only for $$$t>1$$$.

Help Polycarp win the game.

Input Format:
None

Output Format:
None

Note:
In the first test, the $$$[1, 0, 1, 1, 0, 1]$$$ array is hidden. In this test $$$k=2$$$.