//package atcoder;
 
import java.util.*;
//import java.math.BigDecimal;
 
public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		String S = sc.next();
		String find = "ABC";
		int count = 0;
		if(S.contains(find)) {
			//count ++;
			for(int i=2;i<N;i++) {
				if(S.charAt(i-2)=='A'&&S.charAt(i-1)=='B'&&S.charAt(i)=='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