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 cdig = 0,csmall = 0,ccaps = 0,cspecial = 0,count = 0;
        char[] ch = password.toCharArray();
        for(int i = 0;i<ch.length;i++){
            if(java.lang.Character.isDigit(ch[i]))
                cdig++;
            if(java.lang.Character.isLowerCase(ch[i]))
                csmall++;
            if(java.lang.Character.isUpperCase(ch[i]))
                ccaps++;
            if(ch[i]=='!' ||ch[i]=='@' ||ch[i]=='#' ||ch[i]=='$' ||ch[i]=='%' ||ch[i]=='^' ||ch[i]=='&' ||ch[i]=='*' ||ch[i]=='(' ||ch[i]==')' ||ch[i]=='-' ||ch[i]=='+')
                cspecial++;
        }
        if(cdig == 0)
            count++;
        if(csmall == 0)
            count++;
        if(ccaps == 0)
            count++;
        if(cspecial == 0)
            count++;
        int dif = 0;
       // System.out.println(count+" "+password.length());
        if((count + password.length()) < 6){
            dif = 6 - (count+password.length());
            
        }
        return count + dif;
        
        
    }

    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();
    }
}