import re
n = int(input())
s = input()
m = re.findall("ABC", s)
print(len(m))

0959bd2b300647861b43ab919d702a835d1e2f8f
<mask token>

<mask token>
print(len(m))

<mask token>
n = int(input())
s = input()
m = re.findall('ABC', s)
print(len(m))

import re
n = int(input())
s = input()
m = re.findall('ABC', s)
print(len(m))

import re
n = int(input())
s = input()
m = re.findall("ABC", s)
print(len(m))
