import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String s = sc.next();
		int count = 0;
		for (int i = 0; i < n - 2; i++) {
			char first = s.charAt(i);
			char second = s.charAt(i + 1);
			char third = s.charAt(i + 2);
			if (first == 'A' && second == 'B' && third == 'C') {
				count++;
			}
		}
		print(count);
		sc.close();
	}

	public static void print(Object obj) {
		System.out.println(obj);
	}

}

/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