import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static int minimumNumber(int n, String password) {
        String numbers = "0123456789";
        String lower_case = "abcdefghijklmnopqrstuvwxyz";
        String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String special_characters = "!@#$%^&*()-+";
        
        int num = 0;
        int lc = 0;
        int uc = 0;
        int sc = 0;
        int res = 0;
        for (int i = 0; i < n; i++) {
            char c = password.charAt(i);
            if (numbers.indexOf(c) != -1) {
               num++;
            }
            else if (lower_case.indexOf(c) != -1) {
               lc++;
            }
            else if (upper_case.indexOf(c) != -1) {
               uc++;
            }
            else if (special_characters.indexOf(c) != -1) {
               sc++;
            }
        }
        if (num == 0) {
            res++;
        }
        if (lc == 0) {
            res++;
        }
        if (uc == 0) {
            res++;
        }
        if (sc == 0) {
            res++;
        }
        if (n + res < 6) {
            res += 6 - (n + res);
        }
        return res;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String password = in.next();
        int answer = minimumNumber(n, password);
        System.out.println(answer);
        in.close();
    }
}