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: Wrong Answer)

#include <iostream>
#include <string>
using namespace std;

int main(){
    int N;
    cin >> N;

    string str;

    cin >> str;

    int cnt = 0;
    int ans = 0;
    for(int i = 0; i < N; ++i){
       if(str[i] == 'A'){
           ++cnt;
       }else if(cnt == 1 && str[i] == 'B'){
           ++cnt;
       }else if(cnt == 2 && str[i] == 'C'){
           ++ans;
           cnt = 0;
       }else{
           cnt = 0;
       }
    }

    cout << ans << endl;
    
    return 0;
}