import java.util.ArrayDeque;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Map;
import java.util.Queue;
import java.util.Scanner;
import java.util.Set;

public class Main {

	static Scanner sc = new Scanner(System.in);

	public static void main(String[] args){

		solve_abc150_b();
	}
  
  	public static void solve_abc150_b(){
		
		Scanner sc = new Scanner(System.in);
		
		int N = sc.nextInt();
		String S = sc.next();
		String keyword = "ABC";
		int count = 0;
		
		for(int i=0;i<N-(keyword.length()-1);i++){
			
			if(S.substring(i, i+keyword.length()).equals(keyword)){
				count++;
				i += keyword.length() - 1;
			}
		}
		
		System.out.println(count);
		sc.close();
		
	}
}
/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