import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n =  sc.nextInt();
		String s = sc.next();

		int index=0;
		int count=0;

		while(true) {
			if(s.indexOf("ABC",index)!= -1) {
				index = s.indexOf("ABC",index)+3;
			}else {
				break;
			}
			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