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

public class Solution {

    
       static Set<Character> special=new HashSet<>();
        static int minimumNumber(int n, String password) {
        // Return the minimum number of characters to make the password strong
        int lower=0,upper=0,spec=0,dig=0;
        
        for(char c:password.toCharArray()){
            if(c>='a'&&c<='z')  lower++;
            else if(c>='A'&&c<='Z') upper++;
            else if(c>='0'&&c<='9') dig++;
            else if(special.contains(c))  spec++;
        }
            int addn=0;
            if(lower==0)    addn++;
            if(upper==0)    addn++;
            if(spec==0)    addn++;
            if(dig==0)    addn++;
            if(n<6){
                if(addn<(6-n))  addn=6-n;
            }
            return addn;
    }

    public static void main(String[] args) {
        special.add('!');
        special.add('@');
        special.add('#');
        special.add('$');
        special.add('%');
        special.add('^');
        special.add('&');
        special.add('*');
        special.add('(');
        special.add(')');
        special.add('-');
        special.add('+');
    
        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();
    }
}