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

public class Solution {

    static int minimumNumber(String password) {
        // Return the minimum number of characters to make the password strong
        int l=password.length();
        int n=0;
        int count=0;
        for(int i=0;i<l;i++)
        {
            if(password.charAt(i)=='a' ||  password.charAt(i)=='b'  || password.charAt(i)=='c' || password.charAt(i)=='d' || password.charAt(i)=='e' ||  password.charAt(i)=='f' || password.charAt(i)=='g' || password.charAt(i)=='h' || password.charAt(i)=='i' || password.charAt(i)=='j' || password.charAt(i)=='k' || password.charAt(i)=='l' || password.charAt(i)=='m' || password.charAt(i)=='n' || password.charAt(i)=='o' || password.charAt(i)=='p' || password.charAt(i)=='q' || password.charAt(i)=='r' || password.charAt(i)=='s' || password.charAt(i)=='t' || password.charAt(i)=='u' || password.charAt(i)=='v' || password.charAt(i)=='w' || password.charAt(i)=='x' || password.charAt(i)=='y' || password.charAt(i)=='z')
            {
                count++;
                break;
            }
        }
                for(int i=0;i<l;i++)
        {
            if(password.charAt(i)=='A' ||  password.charAt(i)=='B'  || password.charAt(i)=='C' || password.charAt(i)=='D' || password.charAt(i)=='E' ||  password.charAt(i)=='F' || password.charAt(i)=='G' || password.charAt(i)=='H' || password.charAt(i)=='I' || password.charAt(i)=='J' || password.charAt(i)=='K' || password.charAt(i)=='L' || password.charAt(i)=='M' || password.charAt(i)=='N' || password.charAt(i)=='O' || password.charAt(i)=='P' || password.charAt(i)=='Q' || password.charAt(i)=='R' || password.charAt(i)=='S' || password.charAt(i)=='T' || password.charAt(i)=='U' || password.charAt(i)=='V' || password.charAt(i)=='W' || password.charAt(i)=='X' || password.charAt(i)=='Y' || password.charAt(i)=='Z')
            {
                count++;
                break;
            }
        }
                for(int i=0;i<l;i++)
        {
            if(password.charAt(i)=='0' ||  password.charAt(i)=='1'  || password.charAt(i)=='2' || password.charAt(i)=='6' || password.charAt(i)=='5' ||  password.charAt(i)=='4' || password.charAt(i)=='3' || password.charAt(i)=='7' || password.charAt(i)=='8' || password.charAt(i)=='9')
            {
                count++;
                break;
            }
        }
                        for(int i=0;i<l;i++)
        {
            if(password.charAt(i)=='!' ||  password.charAt(i)=='@'  || password.charAt(i)=='#' || password.charAt(i)=='$' || password.charAt(i)=='%' ||  password.charAt(i)=='^' || password.charAt(i)=='&' || password.charAt(i)==')' || password.charAt(i)=='(' || password.charAt(i)=='*' || password.charAt(i)=='+' || password.charAt(i)=='-')
            {
                count++;
                break;
            }
        }
        n=4-count;
        if((l+n)>=6)
            return n;
        n=n+(6-(l+n));
        return n;
    }

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