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 JavaScript (node.js v5.12) (judge verdict: Wrong Answer)

"use strict";
const Main = (input) =>{
   let xs = input.trim().split('\n');
   let N = Number(xs[0]);
   let S = xs[1].split('');
   let ans = 0;
   for(let i=0; i<N-3; i++){
   	if(S[i]+S[i+1]+S[i+2]=='ABC'){
   	  ans++
    }
   }
   console.log(ans);

}
Main(require('fs').readFileSync('/dev/stdin','utf8'));