import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		char[] list = sc.next().toCharArray();
		boolean ch = false, bch=false, bbch=false;
		int Count = 0;
		for(int i = 0; i < N - 2; i++) {
			if(list[i] == 'A' && list[i+1] == 'B' && list[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