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) {
        String numbers = "0123456789";
        String lower_case = "abcdefghijklmnopqrstuvwxyz";
        String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String special_characters = "!@#$%^&*()-+";
        int needed = 0;
        boolean got = false;
        for(int i = 0; i < n; i++) {
            for(char ch : numbers.toCharArray()) {
                if(password.charAt(i) == ch) {
                    got = true;
                    break;
                }
            }
        }
        if(got) needed++;
        got = false;
        for(int i = 0; i < n; i++) {
            for(char ch : lower_case.toCharArray()) {
                if(password.charAt(i) == ch) {
                    got = true;
                    break;
                }
            }
        }
        if(got) needed++;
        got = false;
        for(int i = 0; i < n; i++) {
            for(char ch : upper_case.toCharArray()) {
                if(password.charAt(i) == ch) {
                    got = true;
                    break;
                }
            }
        }
        if(got) needed++;        
        got = false;
        for(int i = 0; i < n; i++) {
            for(char ch : special_characters.toCharArray()) {
                if(password.charAt(i) == ch) {
                    got = true;
                    break;
                }
            }
        }        
        if(got) needed++;
        
        int extra = 4 - needed;
        if(n + extra < 6) {
            extra += 6 - (n + extra);
        }
        return extra;
    }

    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();
    }
}