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) {
        String numbers = "0123456789",
        lower_case = "abcdefghijklmnopqrstuvwxyz",
        upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
        special_characters = "!@#$%^&*()-+";
        int strong=0;
        boolean num,lo,up,sp;num=lo=up=sp=false;
        for(int i=0;i<n;i++){
            if(numbers.contains(password.charAt(i)+""))num=true;
            else if(lower_case.contains(password.charAt(i)+""))lo=true;
            else if(upper_case.contains(password.charAt(i)+""))up=true;
            else if(special_characters.contains(password.charAt(i)+""))sp=true;
        }
        if(num)strong++;
        if(lo)strong++;
        if(up)strong++;
        if(sp)strong++;
        strong =4-strong;
        n=n+strong;
        return strong+(6-n<0?0:6-n);
    }

    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();
    }
}