import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class StrongPassword {

	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		String numbers = "0123456789";
		String lower_case = "abcdefghijklmnopqrstuvwxyz";
		String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
		String special_characters = "!@#$%^&*()-+";

		int n = Integer.parseInt(br.readLine().trim());
		String s = br.readLine().trim();

		int count = 0;
		int bitMap[] = new int[4];

		for (char c : numbers.toCharArray())
			if (s.indexOf(c) != -1) {
				bitMap[0] = 1;
				break;
			}

		for (char c : lower_case.toCharArray())
			if (s.indexOf(c) != -1) {
				bitMap[1] = 1;
				break;
			}

		for (char c : upper_case.toCharArray())
			if (s.indexOf(c) != -1) {
				bitMap[2] = 1;
				break;
			}

		for (char c : special_characters.toCharArray())
			if (s.indexOf(c) != -1) {
				bitMap[3] = 1;
				break;
			}

		for (int k : bitMap)
			if (k == 0)
				count++;

		if (n < 6) {
			if (count < 6 - n )
				count = 6 - n;
		}

		System.out.println(count);
	}

}