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[]) {
        Scanner sc = new Scanner(System.in);
        //A - 500 Yen Coins	   
        // int k = sc.nextInt();
        // int x = sc.nextInt();
        // boolean flg = false;
        // if(k*500>=x) {
        //     // System.out.println("k:"+k*500+"x:"+x);
        //     System.out.println("Yes");
        // } else {
        //     // System.out.println("k:"+k*500+"x:"+x);
        //     System.out.println("No");
        // }

        //B - Count ABC
        int n = sc.nextInt();
        String str = sc.nextLine();
        String s = sc.nextLine();
        int result = 0;
        int cnt = 0;
        while(true) {
            result = s.indexOf("ABC");
            if(result==-1) {
                // System.out.println("in");
                break;
            }
            // System.out.println("cnt:"+cnt);
            s = s.substring(result+3);
            // System.out.println("S:"+s);
            cnt++;
        }
        System.out.println(cnt);

    }
}