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 C++14 (GCC 5.4.1) (judge verdict: Runtime Error)

#include <iostream>
#include <functional>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;


void MyFunc(int n, string s)
{
  bool flag_a = false, flag_b = false;
  int count = 0;

  int i = 0;
  while(1)
  {
    if (s[i] == 'A')
    {
      i++;
      if (s[i] == 'B')
      {
        i++;
        if (s[i] == 'C')
        {
          count++;
        }
      }
    }
    
    i++;
    if (i == n)
      break;
  }

  cout << count << endl;  
}


int main(void)
{
  int N;
  string S;

  cin >> N;
  cin >> S;
  
  function<void(int, string)> func = MyFunc;
  func(N, S);

  return 0;
}