using System;
using System.Text.RegularExpressions;
 
namespace RegExApplication
{
   public class Program
   {
      public static void Main(string[] args)
      {
      	string input = "word1 abcdkl word2";
        Regex regex = new Regex(@"^(?=.*\bword1\b)(?=.*\bword2\b).*$");
         
        Match match = regex.Match(input);
 
    	if (match.Success)
    	{
        	Console.WriteLine(match.Groups[0].Value);
    	}
      }
   }
}