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();
    char[] c = new char[n];
    int ans = 0;
    
    for(int i = 0; i < n; i++){
      c[i] = s.charAt(i);
    }
    for(int i = 0; i < n - 2; i++){
      if(c[i] == 'A' && c[i+1] == 'B' && c[i+2] == 'C'){
        ans += 1;
      }
    }

    System.out.println(ans);
  }
}

/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