using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {
    static int minimumNumber(int n, string password) {
        int[] ar = Enumerable.Repeat(0, 4).ToArray();
        int i;
        for(i=0;i<n;i++){
            if(password[i] >= '0' && password[i] <= '9'){
                ar[0]++;
            }
            else if(password[i] >= 'a' && password[i] <= 'z'){
                ar[1]++;
            }
            else if(password[i] >= 'A' && password[i] <= 'Z'){
                ar[2]++;
            }
            else if(password[i] == '!' || password[i] == '@' || password[i] == '#' || password[i] == '$' || password[i] == '%' || password[i] == '^' || password[i] == '&' || password[i] == '*' || password[i] == '(' || password[i] == ')' || password[i] == '-' || password[i] == '+'){
                ar[3]++;
            }
        }
        int ctr = 0;
        for(i=0;i<4;i++){
            if(ar[i] == 0){
                ctr++;
            }
        }
        if(n + ctr < 6){
            return ctr+(6-n-ctr);
        }
        return ctr;
    }

    static void Main(String[] args) {
        int n = Convert.ToInt32(Console.ReadLine());
        string password = Console.ReadLine();
        int answer = minimumNumber(n, password);
        Console.WriteLine(answer);
    }
}