using System; using System.Collections.Generic; using System.Globalization; using System.Text; using System.Text.RegularExpressions; using System.Reflection;
public class MainClass{
public static void Main(){
Regex r1 = new Regex(@"((abc)*)x(\1)");
string s1 = "abcabcabcxabc";
Console.WriteLine(r1.IsMatch(s1) + "..." + r1.Match(s1).Value);
}
}