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
        int numbers = 0;
        int small = 0;
        int large = 0;
        int special = 0;
        int count = 0;
        for(int i = 0; i < password.length(); i++) {
            char s = password.charAt(i);
            if(s == '0' || s == '1' ||s == '2' ||s == '3' ||s == '4' ||s == '5' ||s == '6' ||s == '7' ||s == '8' ||s == '9') {
                numbers++;
            } else if((int)password.charAt(i) >= 65 && (int)password.charAt(i) <= 90) {
                large++;
            } else if((int)password.charAt(i) >= 97 && (int)password.charAt(i) <= 122) {
                small++;
                //!@#$%^&*()-+
            } else if(s == '!' || s == '@' ||s == '#' ||s == '$' ||s == '%' ||s == '^' ||s == '&' ||s == '*' ||s == '(' ||s == ')' ||
                    s == '-' ||s == '+') {
                special++;
            }
        }

        if(numbers == 0) {
            count++;
        }
        if(large == 0) {
            count++;
        }

        if(small == 0) {
            count++;
        }

        if(special == 0) {
            count++;
        }

        if(n < 6-count) {
            count = 6 - n;
        }
        return count;

    }

    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();
    }
}