using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

class Program
{
    static int Main(string[] args) 
    {
        foreach (string line in args[0] == "-" ? ReadConsole() : File.ReadLines(args[0]))
        {
            Match mm = Regex.Match(line, args[1]);
            if (mm.Success)
            {
                Console.WriteLine(
                    mm.Groups.Count == 1 
                    ? mm.Value 
                    : string.Join("", mm.Groups.OfType<Group>().Skip(1).Select(g => g.Value)));
                return 0;
            }
        }
        return 1;
    }
    
    static IEnumerable<string> ReadConsole() 
    {
        while (true)
        {
            string line = Console.ReadLine();
            if (line == null)
            {
                yield break;
            }
            else
            {
                yield return line;
            }
        }
    }
}