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
        String numbers = "0123456789";
        String lower_case = "abcdefghijklmnopqrstuvwxyz";
        String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String special_characters = "!@#$%^&*()-+";
        boolean num,spc,uppC,lowC;
        num=spc=uppC=lowC=false;
        int i;
        for(i=0;i<n;i++){
            if(numbers.indexOf(""+password.charAt(i)) != -1){
                num = true;
            }
            if(lower_case.indexOf(""+password.charAt(i)) != -1){
                lowC = true;
            }
            if(upper_case.indexOf(""+password.charAt(i)) != -1){
                uppC = true;
            }
            if(special_characters.indexOf(""+password.charAt(i)) != -1){
                spc = true;
            }
        }
        int total = 0;
        if(!num){
            total++;
        }
        if(!uppC)
            total++;
        if(!lowC)
            total++;
        if(!spc)
            total++;
        if((n+total)<6)
            total = 6-n;
        return total;
    }

    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();
    }
}