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) {
        boolean upperCase = false;
        boolean lowerCase = false;
        boolean length = false;
        boolean splC = false;
        boolean numC = false;
        String spl = "!@#$%^&*()-+";
        String numbers = "0123456789";
        String lower_case = "abcdefghijklmnopqrstuvwxyz";
        String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        int c = 0;
        for(int i = 0; i < password.length(); i++){
            for(int j = 0; j < numbers.length(); j++){
                if(password.charAt(i) == numbers.charAt(j)){
                    numC = true;
                    break;
                }
            }
            
            for(int j = 0; j < lower_case.length(); j++){
                if(password.charAt(i) == lower_case.charAt(j)){
                    lowerCase = true;
                    break;
                }
            }
          
            for(int j = 0; j < upper_case.length(); j++){
                if(password.charAt(i) == upper_case.charAt(j)){
                    upperCase = true;
                    break;
                }
            }
           
            for(int j = 0; j < spl.length(); j++){
                if(password.charAt(i) == spl.charAt(j)){
                    splC = true;
                    break;
                }
            }
            
            
        }
        
        if(!splC)
            c = c + 1;
         if(!upperCase)
             c = c + 1;
          if(!lowerCase)
                c = c + 1;
        if(!numC)
                c = c + 1;
        int len = password.length();
        if(len >= 6){
            return c;
        }
        else{
            if(c + password.length() >= 6)
                return c;
            else{
                //System.out.println(c);
                return c + 6 - (password.length() + c);
            }
        }
    }

    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();
    }
}