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: Accepted)

function main(input){
    input = input.split('\n');
    inputN = parseInt(input[0]);
    inputS = input[1];
    leng = inputS.length;
    out = 0;

    for(i=0;i<leng-2;i++){
        if(inputS[i]=='A' && inputS[i+1]=='B' && inputS[i+2]=='C'){
            out++;
        }
    }

    console.log(out);
}

main(require("fs").readFileSync("/dev/stdin", "utf8"));