Bob has written a string

consisting of lowercase English letters, and he is going to play a game with his 3-year-old sister Alice with the string. From now on, we denote

as the length of

,

as the

-th character of

, and

as the substring obtained by concatenating all the characters between the

-th and

-th character of

(that is,

). Note that in this problem all strings are 1-indexed.
The game will last for

rounds. In each round, both of the players need to choose a non-empty substring of

. The player with lexicographically larger string wins the game. If two player chooses the same string, it is considered a draw. Here, for two strings

and

, we say

is lexicographically larger than

if

is a prefix of

and

, or there exists some non-negative integer

such that

and for each

there holds

.
Bob has already know the substring Alice will choose for each round. It is easy for him to win the game, but Alice will be really sad if Bob wins too much. Therefore, Bob wants to choose the lexicographically smallest substring of

that can help him win the game. For each round, help Bob figure out which string he should choose, or determine it is impossible to win.