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() {
  /* code */

  int n=0,e,a=0;
  char str[56] = {0};
  int *p;
  //char d="A",b="B",c="C";

  scanf("%d\n", &e);
  scanf("%s\n", str);

  p = (int *)malloc(e * sizeof(int));


  while (str[n+2] != '\0') {  /* str[n] が終端文字（ヌル文字 '\0'）でない間繰り返す */
    if(str[n]=='A'){
       if(str[n+1]=='B'){
         if(str[n+2]=='C'){
           a++;
         }
       }

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