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) {
        
        int count1=0,count2=0,count3=0,count4=0,c=0;
        for(int i=0;i<password.length();i++)
        {
            char ch=password.charAt(i);
            int x=(int)ch;
            if(x>=65 && x<=90)
            {
                count1++;
            }
            if(x>=97 && x<=122)
            {
                count2++;
            }
            if(x>=48 && x<=57)
            {
                count3++;
            }
            if(ch=='+' || ch=='-' || ch=='(' || ch==')' || ch=='*' || ch=='^' || ch=='$' || ch=='#' || ch=='@' || ch=='!')
            {
                count4++;
            }
        }
        if(password.length()>6)
        {
            if(count1==0)
            {
                c++;
            }
            if(count2==0)
            {
                c++;
            }
            if(count3==0)
            {
                c++;
            }
            if(count4==0)
            {
                c++;
            }
            return c;
        }
        else
        {
            int dif=6-password.length();
            if(count1==0)
            {
                c++;
            }
            if(count2==0)
            {
                c++;
            }
            if(count3==0)
            {
                c++;
            }
            if(count4==0)
            {
                c++;
            }
            if(c>=dif)
            {
                return c;
            }
            else
            {
                return c+(dif-c);
            }
        }// Return the minimum number of characters to make the password strong
    }

    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();
    }
}