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[] ar = password.toCharArray();
        
        char[] numbers = "0123456789".toCharArray();
        //lower_case = "abcdefghijklmnopqrstuvwxyz"
        //upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        char[] special_characters = "!@#$%^&*()-+".toCharArray();
        
        boolean[] satisfy = new boolean[4];
        Arrays.fill(satisfy, false);
        
        
        
        for(int i = 0; i < ar.length; i++){
            for(int j = 0; j < numbers.length; j++){
                if(numbers[j] == ar[i]){
                    satisfy[0] = true;
                    //System.out.println("number");
                    break;
                }
            }
            
            if(Character.isLowerCase(ar[i]))
                satisfy[1] = true;
            
            if(Character.isUpperCase(ar[i]))
                satisfy[2] = true;
            
            for(int j = 0; j < special_characters.length; j++){
                if(special_characters[j] == ar[i]){
                    satisfy[3] = true;
                    //System.out.println("special");
                    break;
                }
            }
            
            
        }
        
        int count = 0;
        
        for(int j = 0; j < satisfy.length; j++){
                if(!satisfy[j])
                    count++;
        }
        
        if(n < 6){
            if(count + n < 6)
                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();
    }
}