B' 2^k teams participate in a playoff tournament. The tournament consists of 2^k - 1 games. They are held as follows: first of all, the teams are split into pairs: team 1 plays against team 2 , team 3 plays against team 4 (exactly in this order), and so on (so, 2^{k-1} games are played in that phase). When a team loses a game, it is eliminated, and each game results in elimination of one team (there are no ties). After that, only 2^{k-1} teams remain. If only one team remains, it is declared the champion; otherwise, 2^{k-2} games are played: in the first one of them, the winner of the game " 1 vs 2 " plays against the winner of the game " 3 vs 4 ", then the winner of the game " 5 vs 6 " plays against the winner of the game " 7 vs 8 ", and so on. This process repeats until only one team remains. For example, this picture describes the chronological order of games with k = 3 : Let the string s consisting of 2^k - 1 characters describe the results of the games in chronological order as follows: Let f(s) be the number of possible winners of the tournament described by the string s . A team i is a possible winner of the tournament if it is possible to replace every ? with either 1 or 0 in such a way that team i is the champion. You are given the initial state of the string s . You have to process q queries of the following form: The first line contains one integer k ( 1 <= k <= 18 ). The second line contains a string consisting of 2^k - 1 characters -- the initial state of the string s . Each character is either ?, 0, or 1. The third line contains one integer q ( 1 <= q <= 2 cdot 10^5 ) -- the number of queries. Then q lines follow, the i -th line contains an integer p and a character c ( 1 <= p <= 2^k - 1 ; c is either ?, 0, or 1), describing the '...