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

public class Solution {

    static boolean containsNumber(String password)
    {
        boolean ans = false;
        for(int i = 0;i<password.length();i++)
        {
            char ch = password.charAt(i);
            if(ch >= 48 && ch <= 57)
                ans = true;
            if(ans)
                break;
        }
        return ans;
    }
    
    static boolean containsSpecial(String password)
    {
        boolean ans = false;
        String special = "!@#$%^&*()-+";
        for(int i = 0;i<special.length();i++)
        {
            char ch = special.charAt(i);
            if(password.indexOf(ch) != -1)
                ans = true;
            if(ans)
                break;
        }
        return ans;
    }
    
    static boolean containsLower(String password)
    {
        boolean ans = false;
        String special = "abcdefghijklmnopqrstuvwxyz";
        for(int i = 0;i<special.length();i++)
        {
            char ch = special.charAt(i);
            if(password.indexOf(ch) != -1)
                ans = true;
            if(ans)
                break;
        }
        return ans;
    }
    
    static boolean containsUpper(String password)
    {
        boolean ans = false;
        String special = "abcdefghijklmnopqrstuvwxyz".toUpperCase();
        for(int i = 0;i<special.length();i++)
        {
            char ch = special.charAt(i);
            if(password.indexOf(ch) != -1)
                ans = true;
            if(ans)
                break;
        }
        return ans;
    }
    
    static int minimumNumber(int n, String password) {
        // Return the minimum number of characters to make the password strong
        int ans = 0;
        if(!containsNumber(password))
            ans++;
        if(!containsSpecial(password))
            ans++;
        if(!containsLower(password))
            ans++;
        if(!containsUpper(password))
            ans++;
        if(n < 6)
        {
            int extra = (6 - n);
            ans = Math.max(ans, extra);
        }
        return ans;
    }

    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();
    }
}