B'This is an interactive problem. There are n words in a text editor. The i -th word has length l_i ( 1 <= q l_i <= q 2000 ). The array l is hidden and only known by the grader. The text editor displays words in lines, splitting each two words in a line with at least one space. Note that a line does not have to end with a space. Let the height of the text editor refer to the number of lines used. For the given width, the text editor will display words in such a way that the height is minimized. More formally, suppose that the text editor has width w . Let a be an array of length k+1 where 1=a_1 < a_2 < ldots < a_{k+1}=n+1 . a is a valid array if for all 1 <= q i <= q k , l_{a_i}+1+l_{a_i+1}+1+ ldots+1+l_{a_{i+1}-1} <= q w . Then the height of the text editor is the minimum k over all valid arrays. Note that if w < max(l_i) , the text editor cannot display all the words properly and will crash, and the height of the text editor will be 0 instead. You can ask n+30 queries. In one query, you provide a width w . Then, the grader will return the height h_w of the text editor when its width is w . Find the minimum area of the text editor, which is the minimum value of w cdot h_w over all w for which h_w neq 0 . The lengths are fixed in advance. In other words, the interactor is not adaptive. The first and only line of input contains a single integer n ( 1 <= q n <= q 2000 ) -- the number of words on the text editor. It is guaranteed that the hidden lengths l_i satisfy 1 <= q l_i <= q 2000 . Begin the interaction by reading n . To make a query, print "? w " (without quotes, 1 <= q w <= q 10^9 ). Then you should read our response from standard input, that is, h_w . If your program has made an invalid query or has run out of tries, the interactor will terminate immediately and your program will get a'...