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 <stdlib.h>
int main(void)
{
	int n;
	scanf("%d", &n);
	char* input = (char*)malloc((n + 1) * sizeof(char));
	scanf("%s", input);
	int tick = 0;
	n -= 2;
	for (int i = 0; i < n;)
	{
		if (*(input + i) == 'A' && *(input + i + 1) == 'B' && *(input + i + 2) == 'C') tick++, i += 3;
		else i++;
	}
	printf("%d", tick);
}