package exercise09;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class EchoFinder implements EchoFinderInterface{


    @Override
    public String getPair(BufferedReader bufReader)
    {
        boolean b = true;
        try
        {
            String s = null , r;
            do
            {
                r = bufReader.readLine();
                if(r.equals(s))
                    return r;
                else
                    s = r;
            }while(b);
        }
        catch (IOException e) {
        // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "";
    }

    @Override
    public BufferedReader getSystemInAsBufferedReader()
    {
        return new BufferedReader(new InputStreamReader(System.in));
    }

    public static void main(String [] args)
    {
        EchoFinder e = new EchoFinder();
        String s = e.getPair(e.getSystemInAsBufferedReader());
        if(s != null)
            System.out.println(s);
    }
}