import java.util.*;
import java.io.*;

class StrongPassword
{
	static class FastReader
    {
        BufferedReader br;
        StringTokenizer st;
 
        public FastReader()
        {
            br = new BufferedReader(new
                     InputStreamReader(System.in));
        }
 
        String next()
        {
            while (st == null || !st.hasMoreElements())
            {
                try
                {
                    st = new StringTokenizer(br.readLine());
                }
                catch (IOException  e)
                {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }
 
        int nextInt()
        {
            return Integer.parseInt(next());
        }
 
        long nextLong()
        {
            return Long.parseLong(next());
        }
 
        double nextDouble()
        {
            return Double.parseDouble(next());
        }
 
        String nextLine()
        {
            String str = "";
            try
            {
                str = br.readLine();
            }
            catch (IOException e)
            {
                e.printStackTrace();
            }
            return str;
        }

    }

    public static void main (String[] args)
    {
    	FastReader reader = new FastReader();

    	String numbers = "0123456789";
		String lower_case = "abcdefghijklmnopqrstuvwxyz";
		String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
		String special_characters = "!@#$%^&*()-+";

		int digits=0, low=0, high=0, unique=0;
		int requiremnet = 0;

		int length = reader.nextInt();
		String input = reader.nextLine();

		for (int i=0; i<length; i++)
		{
			for (int j=0; j<10; j++)
			{
				if (input.charAt(i) == numbers.charAt(j))
					digits++;
			}

			for (int j=0; j<26; j++)
			{
				if (input.charAt(i) == lower_case.charAt(j))
					low++;

				if (input.charAt(i) == upper_case.charAt(j))
					high++;
			}

			for (int j=0; j<special_characters.length(); j++)
			{
				if (input.charAt(i) == special_characters.charAt(j))
					unique++;
			}
		} 

		if (digits == 0)
			requiremnet++;

		if (low == 0)
			requiremnet++;

		if (high == 0)
			requiremnet++;

		if (unique == 0)
			requiremnet++;

		if (requiremnet+input.length() >= 6)
			System.out.println (requiremnet);
		else
			System.out.println (6 - input.length());
    }	
}