/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Integer[] intArray = new Integer[] { 0, 1 , 0 , 2 , 3 , 3 , 5 , 6 , -4 ,6 };
		
		LinkedHashSet<Integer> set = new LinkedHashSet<>();
		HashSet<Integer> alreadyPresent = new HashSet<>();
		for (Integer i : intArray) {
		  if (!set.add(i)) {
		    alreadyPresent.add(i);
		  }
		}
		set.removeAll(alreadyPresent);
		
		ArrayList<Integer> list = new ArrayList<>(set);
		
		System.out.println(list);
	}
}