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

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

    static int minimumNumber(int n, String password) {
        // Return the minimum number of characters to make the password strong
        
        boolean hasDigit = false;
        boolean hasUpper = false;
        boolean hasLower = false;
        boolean hasSpecial = false;
        boolean longEnough = password.length() >=6;
        int rightCriteria = 0;
        
        for (int i = 0; i < n; i++){
            char c = password.charAt(i);
            
            if (hasDigit == false){
                // digit chars 48-57
                hasDigit = Character.isDigit(c);
                //System.out.println("digit: "+hasDigit);
                if (hasDigit){
                    rightCriteria++;
                }
            }
            if (hasUpper == false) {
                // upper chars: 65-90
                hasUpper = Character.isUpperCase(c);
                ///System.out.println("upper: "+hasUpper);
                if (hasUpper){
                    rightCriteria++;
                }
            }
            if (hasLower == false) {
                // lower chars: 97-122
                hasLower = Character.isLowerCase(c);
               // System.out.println("lower: "+hasLower);
                if (hasLower){
                    rightCriteria++;
                }
                
            }
            if (hasSpecial == false) {
                for (int j=0; j<special_characters.length(); j++){
                    if (c==special_characters.charAt(j)){
                        hasSpecial = true;
                        //System.out.println("special: "+hasSpecial);
                        if (hasSpecial){
                            rightCriteria++;
                        }   
                    }
                }
            }
            
        }
        
        int temp = 4-rightCriteria;
            //System.out.println(temp);
        
        if (longEnough == true) {
            
        }
        
        if (n + temp >= 6){
            return temp;
        } else {
            return temp + (6- (n+temp));
        }
        
        
        
        //return 0;
    }

    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();
    }
}

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

/*
Its length is at least 6.
It contains at least one digit.
It contains at least one lowercase English character.
It contains at least one uppercase English character.
It contains at least one special character. The special characters are: !@#$%^&*()-+
*/