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 r2 = new Regex("((abc)|(xyz))*");
Console.WriteLine(r2.Match("abcxyzabcxyzxyzabcabcabc").Value);
}
}