import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
static String numbers = "0123456789";
    static String lower_case = "abcdefghijklmnopqrstuvwxyz";
    static String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    static String special_characters = "!@#$%^&*()-+";
    static int minimumNumber(int n, String password) {
        // Return the minimum number of characters to make the password strong
        int digit = 0, low=0, up=0,special=0;

        for(int i = 0; i<password.length();i++){
            StringBuffer sb = new StringBuffer();
            sb.append(password.charAt(i));
            if(numbers.indexOf(sb.toString())!=-1){
                digit++;
            }
            if(lower_case.indexOf(sb.toString())!=-1){
                low++;
            }
            if(upper_case.indexOf(sb.toString())!=-1){
                up++;
            }
            if(special_characters.indexOf(sb.toString())!=-1){
                special++;
            }
        }
        int count = 0;
        if(digit==0)
            count++;
        if(low==0)
            count++;
        if(up==0)
            count++;
        if(special==0)
            count++;
        if(password.length()>=6){

        }else{
            if((password.length()+count)>=6){
                return count;
            }else{
                return 6-password.length();
            }

        }
        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();
    }
}