import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.util.StringTokenizer;

public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    int n = Integer.parseInt(in.readLine());
    StringTokenizer stk = new StringTokenizer(in.readLine());
    String s = stk.nextToken();  
    int cnt = 0;
    String s_rep = s.replace("ABC","a");

    for (int i = 0; i < s_rep.length(); i++){
      if(s_rep.charAt(i) == 'a')
        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