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

public class Solution {

    private static int minimumNumber(int length, String password) {
        // Return the minimum number of characters to make the password strong
        boolean hasUpperCaseLetter = false;
        boolean hasLowerCaseLetter = false;
        boolean hasDigit = false;
        boolean hasSpecialCharacter = false;

        for(int c = 0; c < password.length(); c++) {
            char currentChar = password.charAt(c);

            if(Character.isUpperCase(currentChar)) {
                hasUpperCaseLetter = true;
            }

            if(Character.isLowerCase(currentChar)) {
                hasLowerCaseLetter = true;
            }

            if(Character.isDigit(currentChar)) {
                hasDigit = true;
            }

            // Special characters: //!@#$%^&*()-+
            if(currentChar == '!'
                    || currentChar == '@'
                    || currentChar == '#'
                    || currentChar == '$'
                    || currentChar == '%'
                    || currentChar == '^'
                    || currentChar == '&'
                    || currentChar == '*'
                    || currentChar == '('
                    || currentChar == ')'
                    || currentChar == '-'
                    || currentChar == '+') {
                hasSpecialCharacter = true;
            }
        }

        int charsToAdd = 0;

        if(!hasUpperCaseLetter) {
            charsToAdd++;
        }
        if(!hasLowerCaseLetter) {
            charsToAdd++;
        }
        if(!hasDigit) {
            charsToAdd++;
        }
        if(!hasSpecialCharacter) {
            charsToAdd++;
        }

        int totalChars = password.length() + charsToAdd;

        if(totalChars < 6) {
            charsToAdd += 6 - totalChars;
        }

        return charsToAdd;
    }

    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();
    }
}