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

public class Solution {
    
    public static final String numbers = "0123456789";
    public static final String lower_case = "abcdefghijklmnopqrstuvwxyz";
    public static final String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    public static final String special_characters = "!@#$%^&*()-+";

    static int minimumNumber(int n, String password) {
        int add = 0;
        add += contains(numbers, password);
        add += contains(lower_case, password);
        add += contains(upper_case, password);        
        add += contains(special_characters, password);
        int b = Math.max(0, 4 - add);
        int a = Math.max(0, 6 - b - password.length());
        //System.out.println(a + ", " + b + "");
        return a + b;
    }
    
    public static final int contains(String pattern, String s) {
        for(int i = 0; i < s.length(); i++) {
            if (pattern.indexOf(s.charAt(i)) > -1) return 1;
        }
        return 0;
    }

    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();
    }
}