Input Format
The first line contains , the number of lines in the XML document.
The next  lines follow containing the XML document.
Output Format
Output a single line, the integer value of the maximum level of nesting in the XML document.

### Problem solution in Python 3 programming language.

import xml.etree.ElementTree as etree

maxdepth = 0
def depth(elem, level):
global maxdepth
level += 1
if (maxdepth < level):
maxdepth = level
for child in elem:
depth(child, level)

if __name__ == '__main__':
n = int(input())
xml = ""
for i in range(n):
xml =  xml + input() + "\n"
tree = etree.ElementTree(etree.fromstring(xml))
depth(tree.getroot(), -1)
print(maxdepth)

#### Second solution

import xml.etree.ElementTree as etree
global maxdepth
maxdepth = -1
def depth(elem, level):
global maxdepth
if (level == maxdepth):
maxdepth += 1
for child in elem:
depth(child, level + 1)
if __name__ == '__main__':
n = int(input())
xml = ""
for i in range(n):
xml =  xml + input() + "\n"
tree = etree.ElementTree(etree.fromstring(xml))
depth(tree.getroot(), -1)
print(maxdepth)

### Problem solution in Python 2 programming language.

import xml.etree.ElementTree as etree

maxdepth = 0
def depth(elem, level):
global maxdepth
level += 1
if (maxdepth < level):
maxdepth = level
for child in elem:
depth(child, level)

if __name__ == '__main__':
n = int(raw_input())
xml = ""
for i in range(n):
xml =  xml + raw_input() + "\n"
tree = etree.ElementTree(etree.fromstring(xml))
depth(tree.getroot(), -1)
print maxdepth