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

public class Solution {
    static final int length = 6;
    static final String numbers = "0123456789";
    static final String lower_case = "abcdefghijklmnopqrstuvwxyz";
    static final String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    static final String special_characters = "!@#$%^&*()-+";
    
    static int minimumNumber(int n, String password) {
        // Return the minimum number of characters to make the password strong
        int errLen = 0;
        if (password.length() < length) {
            errLen = length - password.length();
        }
        
        int errHard = 4;
        boolean[] error = {true, true, true, true};
        for (int i = 0; i < password.length(); i++) {
            String ch = "" + password.charAt(i);
            if (error[0]) {
                if (numbers.contains(ch)) {
                    error[0] = false;
                    errHard--;
                }
            }

            if (error[1]) {
                if (lower_case.contains(ch)) {
                    error[1] = false;
                    errHard--;
                }
            }

            if (error[2]) {
                if (upper_case.contains(ch)) {
                    error[2] = false;
                    errHard--;
                }
            }

            if (error[3]) {
                if (special_characters.contains(ch)) {
                    error[3] = false;
                    errHard--;
                }
            }
        }
        
        return Math.max(errLen, errHard);
    }

    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();
    }
}