import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;

public class Eliminator
{
    private TreeSet<String> potentialDuplicates = new TreeSet<>();
    private HashSet<String> baseline = new HashSet<>();

    public Eliminator(File potentialDuplicateSource, File baselineSource) throws IOException
    {
        populateHashSetFromFile(potentialDuplicateSource, this.potentialDuplicates);
        populateHashSetFromFile(baselineSource, this.baseline);
    }

    public TreeSet<String> unique()
    {
        TreeSet<String> unique = new TreeSet<>();

        for (String potential : this.potentialDuplicates)
            if (!this.baseline.contains(potential))
                unique.add(potential);

        return unique;
    }

    private static void populateHashSetFromFile(File source, Set<String> set) throws IOException
    {
        BufferedReader reader = new BufferedReader(new FileReader(source));

        String line;
        while ((line = reader.readLine()) != null)
            set.add(line);
    }

    public static void main(String[] args) throws Exception
    {
        if (args.length < 2)
        {
            System.err.printf("Usage: java Eliminator <potential_duplicates> <baseline>\n");
            System.exit(1);
        }

        Eliminator eliminator = new Eliminator(new File(args[0]), new File(args[1]));
        for (String unique : eliminator.unique())
            System.out.printf("%s\n", unique);
    }
}