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 10.0.0) (judge verdict: Accepted)

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