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) {
        int total = 0;
        
        String numbers = "0123456789";
        String lc = "abcdefghijklmnopqrstuvwxyz";
        String uc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String sc = "!@#$%^&*()-+";
            
        boolean num_check = false;
        boolean lc_check = false;
        boolean uc_check = false;
        boolean sc_check = false;
            
        for (int i = 0; i < n; i++){
            
            for (int j = 0; j < numbers.length(); j++){
                if (password.charAt(i) == numbers.charAt(j)){
                    num_check = true;
                    break;
                }
            }
            for (int j = 0; j < lc.length(); j++){
                if (password.charAt(i) == lc.charAt(j)){
                    lc_check = true;
                    break;
                }
            }
            for (int j = 0; j < uc.length(); j++){
                if (password.charAt(i) == uc.charAt(j)){
                    uc_check = true;
                    break;
                }
            }
            for (int j = 0; j < sc.length(); j++){
                if (password.charAt(i) == sc.charAt(j)){
                    sc_check = true;
                    break;
                }
            }
        }
        
        if (!num_check){
            total++;
        }
        if (!lc_check){
            total++;
        }
        if (!uc_check){
            total++;
        }
        if (!sc_check){
            total++;
        }
        
        if (n + total < 6){
            return 6 - n;
        }
        return total;
    }

    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();
    }
}