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
        boolean containsDigit = false, containsLower = false, containsUpper = false, containsSpecial = false;
        for(int i = 0 ;i<n;i++) {
            char c = password.charAt(i);
            containsDigit |= (c >= 48 && c<=57);
            containsLower |= (c >= 97 && c<=122);
            containsUpper |= (c >= 65 && c<=90);
            containsSpecial = (containsSpecial || isSpecial(c));
        }
        int t = (containsDigit?0:1) + (containsLower?0:1) + (containsUpper?0:1) + (containsSpecial?0:1);
        if(n>=6) {
            return t;
        }
        else {
            return Math.max(t, 6-n);
        }
    }
    
    static boolean isSpecial(char c) {
        String special = "!@#$%^&*()-+";
        for(int i=0;i<special.length();i++) {
            if(c==special.charAt(i))
                return true;
        }
        return false;
    }

    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();
    }
}