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) {
        if(n<=3)
            return 6-n;
        else
        {
            int flag_lc=1;
            int flag_uc=1;
            int flag_digit=1;
            int flag_special=1;
            
            char ch[]=new char[n];
            ch=password.toCharArray();
            for(char c : ch)
            {
                int temp =(int) c;
                if(temp>=48 && temp<=57)
                {
                    flag_digit=0;
                }
                if(temp>=65 && temp<=90)
                {
                    flag_uc=0;
                }
                if(temp>=97 && temp<=122)
                {
                    flag_lc=0;
                }
            if(c=='!' ||c=='@' ||c=='#' ||c=='$' ||c=='%' ||c=='^' ||c=='&' ||c=='*' ||c=='(' ||c==')' ||c=='-' ||c=='+')
                   flag_special=0;
                
                
            }
            
            return flag_lc+flag_uc+flag_digit+flag_special;
        }
    }

    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);
        if(n+answer<=6)
        {
            answer=6-n;
        }
        System.out.println(answer);
        in.close();
    }
}