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 (Clang 3.8.0) (judge verdict: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>

#define A_CHARACTER 'A'
#define B_CHARACTER 'B'
#define C_CHARACTER 'C'

int main()
{
	int lettersAmount, printOutput = 0;
	char inputChar;
	scanf("%d", &lettersAmount);
	char *letterArray = (char *)calloc(lettersAmount, sizeof(char));

	for (int i = 0; i < lettersAmount; i++)
	{
		scanf("%c", &inputChar);
		letterArray[i] = inputChar;
	}

	for (int i = 0; i < lettersAmount - 2; i++)
	{
		if (letterArray[i] == A_CHARACTER)
		{
			if (letterArray[i + 1] == B_CHARACTER)
			{
				if (letterArray[i + 2] == C_CHARACTER)
				{
					printOutput++;
				}
			}
		}
	}

	printf("%d \n", printOutput);
	return 0;
}