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>
#include <math.h>
int main()
{
	int n;
	char s[50];
	scanf("%d",&n);
	int i=0,q=0,p=0;
	scanf("%s",s);
	for(i=0;i<n;i++)
	{
		p=0;
		if(s[i]=='A'&&i<n-2)
		{
			if(s[i+1]=='B')
			{
				if(s[i+2]=='C')
				{
					p=1;
				}
			}
		}
		if(p==1)
		q++;
	}
	printf("%d",q);
}