public class Main {
	public static void main(String args[]) {
		java.util.Scanner sc = new java.util.Scanner(System.in);
		int N = sc.nextInt();
		String[] S = (sc.next() + " ").split("ABC");

		System.out.print(S.length - 1);
	}
}
/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