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)
    {
        // Return the minimum number of characters to make the password strong
        int len=password.length();
        int p=0;
        if(isdigit(password)==false)
            p++;
        if(isupper(password)==false)
            p++;
        if(islower(password)==false)
            p++;
        if(isspecial(password)==false)
            p++;
        int remlen=6-len;
        int a=(remlen>p)?remlen:p;
        return a;
    }
    public static boolean isdigit(String s)
    {
        for(int i=0;i<s.length();i++)
        {
           if(((s.charAt(i))>=48)&&((s.charAt(i))<=57))
               return true;
        }
        return false;
    }
    public static boolean isupper(String s)
    {
        for(int i=0;i<s.length();i++)
        {
           if(((s.charAt(i))>=65)&&((s.charAt(i))<=90))
               return true;
        }
        return false;
    }
    public static boolean islower(String s)
    {
        for(int i=0;i<s.length();i++)
        {
           if(((s.charAt(i))>=97)&&((s.charAt(i))<=122))
               return true;
        }
        return false;
    }
     public static boolean isspecial(String s)
     {
         char a[]={'!','@','#','$','%','^','&','*','(',')','-','+'};
         for(int i=0;i<s.length();i++)
         {
             for(int j=0;j<12;j++)
             {
                 if(s.charAt(i)==a[j])
                     return true;
             }
         }
         return false;
     }
    
    

    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();
    }
}