import java.math.BigInteger;
import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int count = sc.nextInt();
    String str = sc.next();
    long out = 0;

    for (int i = 0; i < count -2; i++) {
      if ('A' == str.charAt(i) && 'B' == str.charAt(i + 1) && 'C' == str.charAt(i + 2)) {
        out++;
      }
    }
    System.out.println(out);
  }
}
/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