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 (GCC 5.4.1) (judge verdict: Wrong Answer)

// B - Count ACB
#include <stdio.h>

int main(void){
    int n;
    char s[51];
    scanf("%d", &n);
    scanf("%s", s);
    int cnt=0;
    for(int i=0; i<n-3; i++){
        if(s[i] == 'A'){
            if(s[i+1] == 'B'){
                if(s[i+2]) cnt++;
            }
        }
    }
    printf("%d\n", cnt);
    return 0;
}