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 9.2.1) (judge verdict: Accepted)

#include <stdio.h>

int main(){
	int N;
  	char S[50];
  	int count=0;
  	int i;
  	scanf("%d",&N);
  	scanf(" %c",&S[0]);
  	for(i=1;i<N;i++){
      scanf("%c",&S[i]);
  	}
  	for(i=0;i<=N-3;i++){
    	if(S[i]=='A'&&S[i+1]=='B'&&S[i+2]=='C'){
        	count++;
        }
    }
  	printf("%d\n",count);
  	return 0;
}