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 number = false;
        boolean lower = false;
        boolean upper = false;
        boolean spchar = false;
        int res  = 0;
        for(int i = 0;  i < n ; i++){
            char c = password.charAt(i);
            if(c>=48 && c <= 57){
                number = true;
            }else if(c >= 97 && c<= 122){
                lower = true;
            }else if(c>=65 && c<=90){
                upper = true;
            }else if(c=='!' || c=='@' || c== '#' || c=='$' || c=='%' || c=='^' || c=='&' || c=='*' || c=='(' || c==')'|| c=='-' ||c=='+'){
                spchar = true;
            }
        }
        if(!number){
            res++;
        }
        if(!lower){
            res++;
        }
        if(!upper){
            res++;
        }
        if(!spchar){
            res++;
        }
        int rem = 6-(n+res);
        if(rem>0){
            res+=rem;
        }
        return res;
    }

    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();
    }
}