Oh, My Girl!

namespace Oh_My_Girl
{
    using System;
    using System.Text;
    using System.Text.RegularExpressions;

    class OhMyGirl
    {
        static void Main(string[] args)
        {
            string keyPattern = GetKeyPattern();

            StringBuilder text = new StringBuilder();
            string inputLine = Console.ReadLine();
            while (inputLine != "END")
            {
                text.Append(inputLine);
                inputLine = Console.ReadLine();
            }

            StringBuilder result = new StringBuilder();
            MatchCollection matches = Regex.Matches(text.ToString(), keyPattern);
            foreach (Match match in matches)
            {
                result.Append(match.Groups[1].Value);
            }

            Console.WriteLine(result);
        }

        private static string GetKeyPattern()
        {
            string key = Console.ReadLine();
            StringBuilder sb = new StringBuilder();
            if (!char.IsLetterOrDigit(key[0]) && !char.IsWhiteSpace(key[0]))
            {
                sb.Append('\\');
            }

            sb.Append(key[0]);

            for (int i = 1; i < key.Length - 1; i++)
            {
                if (char.IsDigit(key[i]))
                {
                    sb.Append("[0-9]*");
                }
                else if (char.IsUpper(key[i]))
                {
                    sb.Append("[A-Z]*");
                }
                else if (char.IsLower(key[i]))
                {
                    sb.Append("[a-z]*");
                }
                else if (char.IsWhiteSpace(key[i]))
                {
                    sb.Append("\\s");
                }
                else
                {
                    sb.Append('\\').Append(key[i]);
                }
            }

            if (!char.IsLetterOrDigit(key[key.Length - 1]) &&
                !char.IsWhiteSpace(key[key.Length - 1]))
            {
                sb.Append('\\');
            }

            sb.Append(key[key.Length - 1]);

            return (sb + "(.{2,6})" + sb);
        }
    }
}