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 mp make_pair
#define pi 2.0*acos(0.0)
#define INTM 1e18
#define mod 1e9+7
#define FOR(i,j,n)    for(ull i=j;i<n;i++)
#define RFOR(i,j,n)    for(ll i=j;i>=n;i--)

typedef long long int ll;
typedef unsigned long long ull;
typedef long double ld;

int main(){
    ll n;
    cin>>n;
    string s;
    cin>>s;
    ll ans = 0;
    FOR(i,0,n-3){
        if(s[i] == 'A' && s[i+1] == 'B' && s[i+2] == 'C') ans++;
    }
    cout<<ans<<endl;
}