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) {
        int count = 0;
        //int  num = 0;
        boolean digit = false;
        boolean uppercase = false;
        boolean lowercase = false;
        boolean special = false;
        for(int i=0;i<password.length();i++){
            char c = password.charAt(i);
            if(Character.isDigit(c)){
                digit=true;
                continue;
            }
            if(Character.isLetter(c)){
                if(Character.isUpperCase(c)){
                    uppercase = true;
                }
                else{
                    lowercase = true;
                }
                continue;
            }
            else{
                special = true;
            }
        }
        
        int num = 0;
        if(!digit){
            num++;
        }
        if(!uppercase){
            num++;
        }
        if(!lowercase){
            num++;
        }
        if(!special){
            num++;
        }
        
        if(password.length()>=6){
            return num;
        }
        else{
            return Math.max(num,6-password.length());
        }
    }

    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();
    }
}