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
        String numbers = "0123456789";
        String lower_case = "abcdefghijklmnopqrstuvwxyz";
        String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String special_characters = "!@#$%^&*()-+";
        
        int n1 = (int)'0', n2 = (int)'9';
        int l1 = (int)'a', l2=(int)'z';
        int u1 = (int)'A', u2=(int)('Z');
        
        Set<Integer> sc = new HashSet<Integer>();
        for(char ch: special_characters.toCharArray()){
            sc.add((int)ch);
        }
        
        boolean oDigit= false, oLowercase= false, oUpp= false, oSpec = false;
        
        for(char ch: password.toCharArray()){
            int k = (int)ch;
            if(k>=n1 && k<=n2){
                oDigit = true;
            }
            else if(k>=l1 && k<=l2){
                oLowercase = true;
            }else if(k >= u1 && k<=u2){
                oUpp = true;
            }else if(sc.contains(k)){
                oSpec = true;
            } 
        }
        
        int sum = (oDigit? 0:1) + (oLowercase? 0 : 1) + (oUpp ? 0 : 1) + (oSpec? 0 : 1);
        if(n + sum < 6){
            return 6 - n;
        }
        return sum;
        
    }

    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();
    }
}