import java.util.*;

public class Main{

    public static void main(String args[]){

        Scanner scan = new Scanner(System.in);
        Integer n = scan.nextInt();
        String s = new String(scan.next());

        int count = 0;
        while(true){
            int i;
            if((i = s.indexOf("ABC")) != -1){
                count++;
                s = s.substring(i+2);
            }else{
                break;
            }
        }
        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