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 minLength = false, lowerCase = true, upperCase = true, specialChar = true, numbers = true;
        String specialChars = "!@#$%^&*()-+";
        int answer = 0;
        
        if (n < 6) minLength = true;
        
        for (int i = 0; i < n; i++) {
            char c = password.charAt(i);
            
            if (c == '0' || c == '1' || c == '2' || c == '3' || c == '4' || c == '5' || c == '6' || c == '7' || c == '8' || c == '9') {
                numbers = false;
            } else {
                if ((int)c >= 65 && (int)c <= 90) {
                    upperCase = false;
                } else if ((int) c >= 97 && (int)c <= 122) {
                    lowerCase = false;
                } else {
                    if (specialChar) {
                        for (int j = 0; j < specialChars.length(); j++) {
                          char sChars = specialChars.charAt(j);
                            if (c == sChars) {
                                specialChar = false;
                                break;
                            }
                    }
                    }
                }
            }
        }
        
        if (minLength) {
            answer = 6 - n;
            //System.out.println("Minimum length is 6 less "+answer);
        }
        
        int counter = 0;
        if (upperCase) {
           // System.out.println("UPPwer true");
            counter++;
        }
        
        if (lowerCase) {
           // System.out.println("lower true");
            counter++;
        }
        
        if(specialChar) {
           counter++;
        }
        
        if (numbers) {
            counter++;
        }
        
        if (answer < counter) {
            answer += (counter - answer);
        }
        return answer;
    }

    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();
    }
}