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

public class Solution {
    public static boolean isAlpha(String name) {
         return name.matches("[a-zA-Z]+");
    }
    static int minimumNumber(int n, String password) {
        ArrayList<String> numbers = new ArrayList<String>();
        ArrayList<String> special = new ArrayList<String>();
        special.add("&");
        special.add("*");
        special.add("(");
        special.add(")");
        special.add("+");
        special.add("-");
        special.add("^");
        special.add("%");
        special.add("$");
        special.add("#");
        special.add("@");
        special.add("!");
        for(int i = 0; i<=9; i++){
            numbers.add(i+"");
        }
        String[] s = password.split("");
        boolean nums = false;
        boolean spec = false;
        boolean upper = false;
        boolean lower = false;
        for (int i = 0; i < s.length; i++){
            if(numbers.contains(s[i])){
                nums = true;
            }else if(special.contains(s[i])){
                spec = true;
            }else if(isAlpha(s[i])&&s[i].toUpperCase().equals(s[i])){
                upper = true;
            }else if(isAlpha(s[i])&&s[i].toLowerCase().equals(s[i])){
                lower = true;
            }
        }
        int need = 0;
        need += nums==false?1:0;
        need += spec==false?1:0;
        need += upper==false?1:0;
        need += lower==false?1:0;
        int neededc = 0;
        if(password.length()<6){
            neededc = 6- password.length();
        }
        return Math.max(neededc,need);
    }

    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();
    }
}