
import java.util.Arrays;
import java.util.Collections;
import java.util.Scanner;
import java.util.Vector;

public class Main {

	public static void main(String[] arg) {
		Scanner ob=new Scanner(System.in);
		int n=ob.nextInt();
		String s=ob.next();
		int k=0;
		for (int i=0; i<=s.length()-3; i++) {
			if (s.charAt(i)=='A'&&s.charAt(i+1)=='B'&&s.charAt(i+2)=='C') {
				k++;
			}
		}
		System.out.println(k);
	}
}

/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