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) {
        // Return the minimum number of characters to make the password strong
        String numbers = "0123456789";
        String lower_case = "abcdefghijklmnopqrstuvwxyz";
        String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String special_characters = "!@#$%^&*()-+";
        Map<String,Boolean> passes = new Hashtable<>();
        passes.put("containsNum", false);
        passes.put("containsLowerCase", false);
        passes.put("containsUpperCase", false);
        passes.put("containsSpecial_character", false);
        
        int minToAdd = 0;
        for(int i = 0; i < n; ++i){
            if(numbers.contains("" + password.charAt(i))){ 
                passes.put("containsNum", true);
            }
            else if(lower_case.contains("" + password.charAt(i))){
                passes.put("containsLowerCase", true); 
            }
            else if(upper_case.contains("" + password.charAt(i))){
                 passes.put("containsUpperCase", true);
            }
            else if(special_characters.contains("" + password.charAt(i))){
                  passes.put("containsSpecial_character", true);
            }
        }
        
        Iterator<String> it = passes.keySet().iterator();
        while(it.hasNext()){
            String key = it.next();
            if(passes.get(key) == false){
                minToAdd++;
            }
        }
        if(n + minToAdd < 6){
            minToAdd += 6 - (n + minToAdd);
        }
        
        return minToAdd;
    }

    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();
    }
}