import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    final String s = scanner.nextLine();
    final int n = Integer.parseInt(s);
    final String s2 = scanner.nextLine();

    final String[] split = s2.split("");
   
    int a = 0;
    for (int i = 0; i <= n - 3; i++) {
      if (split[i].equals("A")
          && split[i+1].equals("B")
          && split[i+2].equals(("C"))) {
        a++;
      }
    }
    System.out.println(a);
  }
}

/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