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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		// 入力値
		int n = sc.nextInt();
		char[] s = sc.next().toCharArray();
		sc.close();
		//char[] abc = {'A','B','C'};
		int cnt = 0;
		//int abccnt = 0;
		for(int i=0;i<n-2;i++){
			if(s[i]=='A' && s[i+1]=='B' && s[i+2]=='C') cnt++;
			/*
			if(s[i]==abc[abccnt]){
				abccnt++;
			}else{
				abccnt=0;
			}
			if(abccnt==3){
				abccnt=0;
				cnt++;
			}
			*/
		}
		System.out.println(cnt);
    }
}