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 cnt = 0;

		Character[] n= new Character[51];

		for(int i=0; i < S.length(); i++) {
			n[i] = S.charAt(i);
		}

		for(int i=2; i < N; i++) {
			if(n[i-2] == 'A' && n[i-1] == 'B' && n[i] == '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