Problem Description

An adventure game maintains a command library that contains $n$ distinct full commands.

The player will input $m$ strings one by one as input commands. An input command can be a full command itself, or a prefix of some full command (continuous matching starting from the 1st character).

For each input command $s$, define its matching result with the command library as follows:

• If there exists exactly one full command $c$ such that $s$ is a prefix of $c$, then $s$ is considered to uniquely match $c$. The system executes that command and outputs $c$.
• If two or more full commands use $s$ as a prefix, then $s$ is considered a multiple match, and output ambiguous.
• If there is no full command in the library that has $s$ as a prefix, then $s$ is considered unable to match, and output unknown.

Now, for each command entered by the player, output its matching result according to the rules above.

Input Format

The first line contains two integers $n, m$, representing the number of full commands in the command library and the number of input commands from the player.

The next $n$ lines each contain a string, representing a full command.

The next $m$ lines each contain a string, representing an input command.

Output Format

Output $m$ lines. The $i$-th line is the matching result for the $i$-th input command:

• Unique match: output the corresponding full command.
• Multiple match: output ambiguous.
• Unable to match: output unknown.

6 5
attack
defend
move
magic
examine
exit
att
def
mov
ex
e

attack
defend
move
ambiguous
ambiguous

4 4
open
close
operate
unlock
op
clo
un
cast

ambiguous
close
unlock
unknown

Hint

Sample Explanation 1

The command library is: attack, defend, move, magic, examine, exit.

• att is a prefix of attack and matches only this one, so output attack.
• def matches only defend, so output defend.
• mov matches only move, so output move.
• ex matches both examine and exit, so it is a multiple match, output ambiguous.
• e matches both examine and exit, so output ambiguous.

Sample Explanation 2

• op matches both open and operate, so output ambiguous.
• clo matches only close, so output close.
• un matches only unlock, so output unlock.
• cast cannot match any full command, so output unknown.

Constraints

For $30\%$ of the testdata, $n \leq 10$ and $m \leq 10$.

For $60\%$ of the testdata, $n \leq 50$ and $m \leq 50$.

For all testdata, $1 \leq n \leq 100$ and $1 \leq m \leq 100$.

It is guaranteed that the lengths of all command names and input commands are within $[1, 20]$, all strings contain only lowercase English letters, and all full commands in the command library are distinct.

Translated by ChatGPT 5