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 <bits/stdc++.h>
using namespace std;

#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define endl '\n'
#define fcin ios::sync_with_stdio(false); cin.tie(nullptr);
#define INF 0x3f3f3f3f
#define all(x) x.begin(), x.end()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef long long ll;
typedef pair<int, int> pii;

int main(){
    fcin;
    int n;
    cin >> n;
    string s;
    cin >> s;

    string p = "ABC";

    int ans = 0;
    for(int i = 0; i < n - 3; i++){
        if(s[i] == 'A' and s[i+1] == 'B' and s[i+2] == 'C') ans++;
    }

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