import java.util.*;
import java.io.*;

public class Main {
 
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();   
        String s = sc.next();
        int cnt = 0;
        for (int i = 0; i < n-2; i++) {
            if (s.charAt(i) == 'A') {
                if (s.charAt(i+1) == 'B') {
                    if (s.charAt(i+2) =='C') {
                        cnt++;
                    }
                }
            }
        }        
        
        System.out.println(cnt);
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz