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: Accepted)

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>

#define GYOU_MAX 256
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define s_pri(str) printf("%s\n",str);
#define PRINT(str) printf(#str "\n")
#define v_pri(val) printf("%d\n",val);
#define FOR(i, m, n) for(int i = m; i < n; i++)
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
#define pi acos(-1.0)
#define sca(x) scanf("%d",&x);

typedef long long int ll;


int main(void) {
	
	char S[51];
	int N;
	
	sca(N);
	scanf("%s", S);
	int count = 0;
	rep(i, strlen(S)-2) {
		if (S[i] == 'A'&&S[i + 1] == 'B'&&S[i + 2] == 'C') {
			count++;
		}
	}
	v_pri(count);

	return 0;
}