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
        
        boolean num= false;
        boolean lowerCase= false;
        boolean upperCase= false;
        boolean special= false;
        
            for(int i=0; i<n; i++)
            {
                char ch= password.charAt(i);
                
                if(ch>='0' && ch<='9')
                {
                    num= true;
                }
                else if(ch>='a' && ch<='z')
                {
                    lowerCase= true;
                }
                else if(ch>='A' && ch<='Z')
                {
                    upperCase= true;
                }
                else if(ch=='!' || ch=='@' || ch=='#'|| ch=='$'|| ch=='%'|| 
                        ch=='^'|| ch=='&'|| ch=='*'|| ch=='('|| ch==')'|| ch=='-'|| ch=='+')
                {
                    special=true;
                }
            }
        
        int count=0;
        if(!num)
            count++;
        
        if(!lowerCase)
            count++;
        
        if(!upperCase)
            count++;
        
        if(!special)
            count++;
        
        if(n+count <6)
        {
            return 6-n;
        }else
        {
            return count;
        }
            
    }

    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();
    }
}