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
           int totalChar = password.length();  
        int upperCase = 0,count=0;  
        int lowerCase = 0;  
        int digits = 0;  
        int others = 0;  
        for (int i = 0; i < password.length(); i++) {  
            char ch = password.charAt(i);  
            if (Character.isUpperCase(ch)) {  
                upperCase++;  
            }  
            else if (Character.isLowerCase(ch)) {  
                lowerCase++;  
            }  
            else if (Character.isDigit(ch)) {  
                digits++;  
            }  
            else {  
                others++;  
            }  
        }  
            if(upperCase==0)
                count++;
              if(lowerCase==0)
                count++;
              if(digits==0)
                count++;
              if(others==0)
                count++;
         if(count+n<6)
        {
             count+=(6-count-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();
    }
}