Buggy python submission (verdict: Runtime Error):
import sys
readline = sys.stdin.readline

class Node:
    def __init__(self, sigma, depth):
        self.end = False
        self.child = [None] * sigma
        self.depth = depth
    def __setitem__(self, i, x):
        self.child[i] = x
    def __getitem__(self, i):
        return self.child[i]

class Trie():
    def __init__(self, sigma):
        self.sigma = sigma
        self.root = Node(sigma, 0)
    
    def add(self, S):
        vn = self.root
        for cs in S:
            if vn[cs] is None:
                vn[cs] = Node(sigma, vn.depth + 1)
            vn = vn[cs]
        vn.end = True

ans = 0

N, L = map(int, readline().split())

Tr = Trie(2)

for _ in range(N):
    S = list(map(int, readline().strip()))
    Tr.add(S)

cnt = 0
stack = [Tr.root]
while stack:
    vn = stack.pop()
    for i in range(2):
        if vn[i] is None:
            r = L - vn.depth
            cnt ^= -r&r
        else:
            stack.append(vn[i])

print('Alice' if cnt else 'Bob')

Fixed submission:
import sys
readline = sys.stdin.readline

class Node:
    def __init__(self, sigma, depth):
        self.end = False
        self.child = [None] * sigma
        self.depth = depth
    def __setitem__(self, i, x):
        self.child[i] = x
    def __getitem__(self, i):
        return self.child[i]

sigma = 2
root = Node(sigma, 0)
def add_trie(S):
    vn = root
    for cs in S:
        if vn[cs] is None:
            vn[cs] = Node(sigma, vn.depth + 1)
        vn = vn[cs]
    vn.end = True

ans = 0

N, L = map(int, readline().split())

for _ in range(N):
    S = list(map(int, readline().strip()))
    add_trie(S)

cnt = 0
stack = [root]
while stack:
    vn = stack.pop()
    for i in range(2):
        if vn[i] is None:
            r = L - vn.depth
            cnt ^= -r&r
        else:
            stack.append(vn[i])

print('Alice' if cnt else 'Bob')

Buggy python submission (verdict: Time Limit Exceeded):
import sys
readline = sys.stdin.readline

N, L = map(int, readline().split())
node = set([1])
for _ in range(N):
    S = list(map(int, readline().strip()))
    pre = 1
    for s in S:
        vn = 2*pre + s
        if vn not in node:
            node.add(vn)
        pre = vn
cnt = 0
for d in node:
    if (2*d in node) ^ (2*d + 1 in node):
        depth = L-d.bit_length()+1
        cnt ^= (-depth&depth)

print('Alice' if cnt else 'Bob')  

Fixed submission:
import sys
readline = sys.stdin.readline

class Node:
    def __init__(self, sigma, depth):
        self.end = False
        self.child = [None] * sigma
        self.depth = depth
    def __setitem__(self, i, x):
        self.child[i] = x
    def __getitem__(self, i):
        return self.child[i]

sigma = 2
root = Node(sigma, 0)
def add_trie(S):
    vn = root
    for cs in S:
        if vn[cs] is None:
            vn[cs] = Node(sigma, vn.depth + 1)
        vn = vn[cs]
    vn.end = True

ans = 0

N, L = map(int, readline().split())

for _ in range(N):
    S = list(map(int, readline().strip()))
    add_trie(S)

cnt = 0
stack = [root]
while stack:
    vn = stack.pop()
    for i in range(2):
        if vn[i] is None:
            r = L - vn.depth
            cnt ^= -r&r
        else:
            stack.append(vn[i])

print('Alice' if cnt else 'Bob')

Buggy python submission (verdict: Time Limit Exceeded):
import sys
readline = sys.stdin.readline

N, L = map(int, readline().split())
node = set([1])
for _ in range(N):
    S = list(map(int, readline().strip()))
    ls = len(S)
    pre = 1
    for s in S:
        vn = 2*pre + s
        if vn not in node:
            node.add(vn)
        pre = vn
cnt = 0
for d in node:
    h = 0
    if 2*d in node:
        h += 1
    if 2*d+1 in node:
        h += 1
    if h == 1:
        depth = L-d.bit_length()+1
        cnt ^= (-depth&depth)

print('Alice' if cnt else 'Bob')        


Fixed submission:
import sys
readline = sys.stdin.readline

class Node:
    def __init__(self, sigma, depth):
        self.end = False
        self.child = [None] * sigma
        self.depth = depth
    def __setitem__(self, i, x):
        self.child[i] = x
    def __getitem__(self, i):
        return self.child[i]

sigma = 2
root = Node(sigma, 0)
def add_trie(S):
    vn = root
    for cs in S:
        if vn[cs] is None:
            vn[cs] = Node(sigma, vn.depth + 1)
        vn = vn[cs]
    vn.end = True

ans = 0

N, L = map(int, readline().split())

for _ in range(N):
    S = list(map(int, readline().strip()))
    add_trie(S)

cnt = 0
stack = [root]
while stack:
    vn = stack.pop()
    for i in range(2):
        if vn[i] is None:
            r = L - vn.depth
            cnt ^= -r&r
        else:
            stack.append(vn[i])

print('Alice' if cnt else 'Bob')

Buggy python submission (verdict: Runtime Error):
        import sys
        readline = sys.stdin.readline
        
        N, L = map(int, readline().split())
        node = set([1])
        for _ in range(N):
            S = list(map(int, readline().strip()))
            ls = len(S)
            pre = 1
            for s in S:
                vn = 2*pre + s
                if vn not in node:
                    node.add(vn)
                pre = vn
        cnt = 0
        for d in node:
            h = 0
            if 2*d in node:
                h += 1
            if 2*d+1 in node:
                h += 1
            if h == 1:
                depth = L-d.bit_length()+1
                cnt ^= (-depth&depth)
        
        print('Alice' if cnt else 'Bob')        


Fixed submission:
import sys
readline = sys.stdin.readline

class Node:
    def __init__(self, sigma, depth):
        self.end = False
        self.child = [None] * sigma
        self.depth = depth
    def __setitem__(self, i, x):
        self.child[i] = x
    def __getitem__(self, i):
        return self.child[i]

sigma = 2
root = Node(sigma, 0)
def add_trie(S):
    vn = root
    for cs in S:
        if vn[cs] is None:
            vn[cs] = Node(sigma, vn.depth + 1)
        vn = vn[cs]
    vn.end = True

ans = 0

N, L = map(int, readline().split())

for _ in range(N):
    S = list(map(int, readline().strip()))
    add_trie(S)

cnt = 0
stack = [root]
while stack:
    vn = stack.pop()
    for i in range(2):
        if vn[i] is None:
            r = L - vn.depth
            cnt ^= -r&r
        else:
            stack.append(vn[i])

print('Alice' if cnt else 'Bob')