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 <stdio.h>
using namespace std;
bool kt(char s1, char s2)
{
    if (s1 + 1 == s2) return true;
    return false;
}
int main()
{
    //freopen("test.inp","r",stdin);
    string s;
    int n, i, j, res = 0;
    cin >> n >> s;
    int tmp;
    for (i = 0; i <= n-1; i++)
    {
        j = i;
        while (kt(s[j],s[j+1])) j++;
        if (j-i+1 >= 3) {res ++;i++;}
    }
    cout << res;
    return 0;
}