atcoder#ARC087C. [ARC087E] Prefix-free Game

[ARC087E] Prefix-free Game

Score : 700700 points

Problem Statement

For strings ss and tt, we will say that ss and tt are prefix-free when neither is a prefix of the other.

Let LL be a positive integer. A set of strings SS is a good string set when the following conditions hold true:

  • Each string in SS has a length between 11 and LL (inclusive) and consists of the characters 0 and 1.
  • Any two distinct strings in SS are prefix-free.

We have a good string set S={s1,s2,...,sN}S = \{ s_1, s_2, ..., s_N \}. Alice and Bob will play a game against each other. They will alternately perform the following operation, starting from Alice:

  • Add a new string to SS. After addition, SS must still be a good string set.

The first player who becomes unable to perform the operation loses the game. Determine the winner of the game when both players play optimally.

Constraints

  • 1N1051 \leq N \leq 10^5
  • 1L10181 \leq L \leq 10^{18}
  • s1s_1, s2s_2, ..., sNs_N are all distinct.
  • { s1s_1, s2s_2, ..., sNs_N } is a good string set.
  • s1+s2+...+sN105|s_1| + |s_2| + ... + |s_N| \leq 10^5

Input

Input is given from Standard Input in the following format:

NN LL

s1s_1

s2s_2

::

sNs_N

Output

If Alice will win, print Alice; if Bob will win, print Bob.

2 2
00
01
Alice

If Alice adds 1, Bob will be unable to add a new string.

2 2
00
11
Bob

There are two strings that Alice can add on the first turn: 01 and 10. In case she adds 01, if Bob add 10, she will be unable to add a new string. Also, in case she adds 10, if Bob add 01, she will be unable to add a new string.

3 3
0
10
110
Alice

If Alice adds 111, Bob will be unable to add a new string.

2 1
0
1
Bob

Alice is unable to add a new string on the first turn.

1 2
11
Alice
2 3
101
11
Bob