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 = "!@#$%^&*()-+";
        
        boolean hasNum = false, lc = false, uc = false, sc = false;
        int req = 4;
        int answer;
        
        for(int i=0; i < numbers.length();i++) {
            if (password.contains(numbers.charAt(i)+"")) {
                hasNum = true;
                break;
            }
        }
        
        for(int i=0; i < lower_case.length();i++) {
            if (password.contains(lower_case.charAt(i)+"")) {
                lc = true;
                break;
            }
        }
        
        for(int i=0; i < upper_case.length();i++) {
            if (password.contains(upper_case.charAt(i)+"")) {
                uc = true;
                break;
            }
        }
        
        for(int i=0; i < special_characters.length();i++) {
            if (password.contains(special_characters.charAt(i)+"")) {
                sc = true;
                break;
            }
        }
        
        if (n>=6) {
            if (hasNum) {
                req--;
            }
            if (lc) {
                req--;
            }
            if (uc) {
                req--;
            }
            if (sc) {
                req--;
            }
            answer = req;
        } else {
            if (hasNum) {
                req--;
            }
            if (lc) {
                req--;
            }
            if (uc) {
                req--;
            }
            if (sc) {
                req--;
            }
            int howMuchLeft = 0;
            if (n+req >= 6) {
                answer = req;
            } else {
                answer = 6 - (n+req) + req;
            }
        }
        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();
    }
}