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

public class Solution {
 static final String numbers = "0123456789";
    static final String lower_case = "abcdefghijklmnopqrstuvwxyz";
    static final String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    static final String special_characters = "!@#$%^&*()-+";



    public static void main(String[] args) {
       Scanner in = new Scanner(System.in);
        int n = in.nextInt();

        String line = in.next();


        boolean hasNumber;
        boolean haslower;
        boolean hasUpper;
        boolean hasSpecial;

        hasNumber = line.chars().filter(i -> numbers.contains(String.valueOf((char) i))).count() > 0;
        haslower = line.chars().filter(i -> lower_case.contains(String.valueOf((char) i))).count() > 0;
        hasUpper = line.chars().filter(i -> upper_case.contains(String.valueOf((char) i))).count() > 0;
        hasSpecial = line.chars().filter(i -> special_characters.contains(String.valueOf((char) i))).count() > 0;


        System.out.println(

                Math.max(6- line.length(),
                        (hasNumber ? 0 : 1) +
                                (haslower ? 0 : 1) +
                                (hasUpper ? 0 : 1) +
                                (hasSpecial ? 0 : 1)

                )
        );


        in.close();
    }
}