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<cmath>
#include<algorithm>
#include<vector>
#include<functional>
#include<string>
#include<iomanip>
#include<map>
#include<utility>
#include<string>
#include<unordered_map>
#include <queue>

template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }

using namespace std;

#define min_3(a, b, c) min(a, min(b, c))
#define max_3(a, b, c) max(a, max(b, c))
typedef long long ll;

int main(){
    int n, ans = 0;
    string s;
    cin >> n >> s;
    for(int i = 0; i+3 < n; i++){
        if(s.substr(i, 3) == "ABC") ans++;
    }
    cout << ans << endl;
    return 0;
}