5-ta

using System;
using System.Text.RegularExpressions;

namespace Key_Replacer
{
    class Program
    {
        static void Main(string[] args)
        {
            var pattern = @"([A-Za-z]+)([\|<\\])(.*)([\|<\\])([A-Za-z]+)";
            string input = Console.ReadLine();
            Match begin = Regex.Match(input, pattern);
            string start = begin.Groups[1].Value;
            string end = begin.Groups[5].Value;
            string input2 = Console.ReadLine();
            var pattern2 = $@"{start}(.*?){end}";
            MatchCollection result = Regex.Matches(input2, pattern2);
            if (result.Count > 0)
            {
                foreach (Match item in result)
                {
                    Console.Write(item.Groups[1].Value);
                }
            }
            else
            {
                Console.WriteLine("Empty result");
            }
        }
    }
}