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) {
        char[] p = password.toCharArray();
        boolean num,upper,lower,special;
        num = false;
        upper = false;
        lower = false;
        special = false;
            
        String s = "!@#$%^&*()-+";
        for(int i = 0; i < p.length; i++)
        {
            if(!num && Character.isDigit(p[i]))
                num = true;
            else if(!upper && Character.isUpperCase(p[i]))
                upper = true;
            else if(!lower && Character.isLowerCase(p[i]))
                lower = true;
            else if(!special && s.contains(Character.toString(p[i])))
                special = true;
        }
        int need = 0;
        if(!upper)
            need ++;
        if(!lower)
            need++;
        if(!special)
            need++;
        if(!num)
            need++;
        return Math.max(need,6-n);
        // 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();
    }
}