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

public class Solution {

    static boolean isSpecialCharacter(char c) {
        String specialCharacters = "!@#$%^&*()-+";
        String strlCharactersArray = Character.toString(c);
        return specialCharacters.contains(strlCharactersArray);
    }
    
    static int minimumNumber(int n, String password) {
        
        int isDigit = 0;
        int isLowerCase = 0;
        int isUpperCase = 0;
        int isSpChar = 0;
        
        char[] passArr = password.toCharArray();
        
        for(int i = 0; i < passArr.length; i++) {
            
            if(isDigit == 0 && Character.isDigit(passArr[i])) {
                isDigit = 1;
            }
            
            if(isLowerCase == 0 && Character.isLowerCase(passArr[i])) {
                isLowerCase = 1;
            }
            
            if(isUpperCase == 0 && Character.isUpperCase(passArr[i])) {
                isUpperCase = 1;
            }
            
            if(isSpChar == 0 && isSpecialCharacter(passArr[i])) {
                isSpChar = 1;
            }
        }
        
        int add = 0;
        if(isDigit == 0) {
            add++;
        }
        if(isLowerCase == 0) {
            add++;
        }
        if(isUpperCase == 0) {
            add++;
        }
        if(isSpChar == 0) {
            add++;
        }
        int diff = 6 - n;
        
        if(diff > add) {
            return diff;
        }
        
       return add; 
    }

    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();
    }
}