import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc=new Scanner(System.in);
		
		int n=sc.nextInt();
		String s=sc.next();

		char[]c=s.toCharArray();
		 
		int a= 0;
		for(int i = 0; i <= n-3; i ++) {
			if(c[i]=='A'&&c[i+1]=='B'&&c[i+2]=='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