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 basicReq=4;
       String number="1234567890";
        for(int i=0;i<number.length();i++)
        {
            if(password.contains(""+number.charAt(i)))
            {
              basicReq--;
              break;  
            }
        }    
        
        String lower_case = "abcdefghijklmnopqrstuvwxyz";
         for(int i=0;i<lower_case.length();i++)
        {
            if(password.contains(""+lower_case.charAt(i)))
            {
              basicReq--;
              break;  
            }
        }   
        
       String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
         for(int i=0;i<upper_case.length();i++)
        {
            if(password.contains(""+upper_case.charAt(i)))
            {
              basicReq--;
              break;  
            }
        }   
        
       String special_characters = "!@#$%^&*()-+"; 
        for(int i=0;i<special_characters.length();i++)
        {
            if(password.contains(""+special_characters.charAt(i)))
            {
              basicReq--;
              break;  
            }
        }       
        
        if(len+basicReq>=6)
        {
          return basicReq;  
        } 
        
        else
        {
          int extra=6-(len+basicReq); 
          return basicReq+extra;  
            
        }    
    }

    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();
    }
}