import java.util.*;
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<=s.length()-3;i++){
        	if(s.charAt(i) == 'A' && s.charAt(i+1) == 'B' && 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