Problem:
Score : 200 points

Problem Statement

We have a string S of length N consisting of uppercase English letters.

How many times does ABC occur in S as contiguous subsequences (see Sample Inputs and Outputs)?

Constraints

3 \leq N \leq 50

S consists of uppercase English letters.

Input

Input is given from Standard Input in the following format:

N
S

Output

Print number of occurrences of ABC in S as contiguous subsequences.

Sample Input 1

10
ZABCDBABCQ

Sample Output 1

2

Two contiguous subsequences of S are equal to ABC: the 2-nd through 4-th characters, and the 7-th through 9-th characters.

Sample Input 2

19
THREEONEFOURONEFIVE

Sample Output 2

0

No contiguous subsequences of S are equal to ABC.

Sample Input 3

33
ABCCABCBABCCABACBCBBABCBCBCBCABCB

Sample Output 3

5

Solution in Python (3.4.3) (judge verdict: Accepted)

N = int(input())
S = input()

Slist = list(S)

count = 0

Slist.append('0')
Slist.append('0')

for i in range(N):
  if Slist[i] == 'A':
    if Slist[i+1] == 'B':
      if Slist[i+2] == 'C':
        count = count + 1


print(count)

#print('N = ', N)
#print('S = ', S)
#print('Slist = ', Slist)