"""
# Definition for a Node.
class Node:
def __init__(self, val=None, children=None):
self.val = val
self.children = children
"""
import queue
class Solution:
def maxDepth(self, root: 'Node') -> int:
depth =0
if not root:
return 0
q = queue.Queue()
q.put(root)
while not q.empty():
depth += 1
for _ in range(q.qsize()):
node = q.get()
for c in node.children:
if c:
q.put(c)
return depth
