import java.util.*;
import java.io.*;
import java.math.BigInteger;
 
public class Main {
	
	public static void main(String[] args) {
	Scanner s = new Scanner(System.in);
	int N = s.nextInt();
	String S = s.next();

	int count = 0;
	int abc = 0;
	for(int i = 0; i < S.length()-2; i++){
		if(S.charAt(i) == 'A' && S.charAt(i+1) == 'B' && S.charAt(i+2) == 'C'){
			count++;
		}
		
	}
	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