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) {
		int count = 0;
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		char [ ] str = sc.next().toCharArray();
		
		/* debug
		System.out.println(N);
		for(int i = 0; i < str.length; i++) {
			System.out.println(str[i]);
		}
		*/
		
		for(int i = 0; i < N-2; i++) {
			//System.out.println(String.format("%c%c%c", str[i], str[i+1], str[i+2]));
			if(String.format("%c%c%c", str[i], str[i+1], str[i+2]).equals("ABC")) {
				count++;
			}
		}
		
		System.out.println(count);
		
		sc.close();
	}

}