03

using System;

public class P01ValidUsernames {
    public static void Main(string[] args) {
        string[] usernamesArr = Console.ReadLine().Split(", ");

        foreach (string username in usernamesArr) {
            if (IsValidUsername(username)) {
                Console.WriteLine(username);
            }
        }
    }

    private static bool IsValidUsername(string username) {
        bool isValidLength = username.Length >= 3 && username.Length <= 16;
        bool isValidSymbol = true;
        foreach (char ch in username) {
            if (!char.IsLetterOrDigit(ch) && ch != '-' && ch != '_') {
                isValidSymbol = false;
                break;
            }
        }
        return isValidLength && isValidSymbol;
    }
}