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 count=4;
        if(password.matches(".*\\d+.*"))
            count--;
        if(password.matches(".*[a-z]+.*"))
            count--;
        if(password.matches(".*[A-Z]+.*"))
            count--;
        if(password.matches(".*[$&+,:;=?@#|'<>.^*()%!-]+.*"))
            count--;
        if(password.length()+count<6)
            return 6-password.length();
        else 
            return count;
            
        // Return the minimum number of characters to make the password strong
    }

    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();
    }
}