package eecs1022;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Duplicates 
{
    public static void main(String[] args) throws FileNotFoundException 
    {
	String name = "Lab1.ePost";
	File file = new File(name);
	Scanner input = new Scanner(file);
	Set<String> entries = new HashSet<String>();
	while (input.hasNextLine())
	{
	    String line = input.nextLine();
	    String[] part = line.split("\\s+");
	    String ppy = part[0];
	    boolean duplicate = !entries.add(ppy);
	    if (duplicate)
	    {
		System.out.println(ppy);
	    }
	}
	input.close();
    }
}