import java.util.*;
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++){
         if(s.charAt(i)=='A'&&s.charAt(i+1)=='B'&&s.charAt(i+2)=='C'){
            count++;
         }        
      }
      System.out.println(count);            
   }
}
/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