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

class Kamus {
	private Map<String, LinkedHashSet<String>> data = new HashMap<>();
	
	private void hubungkan(String a, String b) {
		if (a.equals(b)) {
			return;
		}
		if (!data.containsKey(a)) {
			data.put(a, new LinkedHashSet<String>());
		}
		data.get(a).add(b);
	}
	
	public void tambah(String kata, String[] sinonim) {
		for (int i = 0; i <sinonim.length; i++) {
			hubungkan(kata, sinonim[i]);
			hubungkan(sinonim[i], kata);
		}
	}
	
	public String[] ambilSinonim(String kata) {
		LinkedHashSet<String> hasil = data.get(kata);
		if (hasil == null) {
			return null;
		}
		return hasil.toArray(new String[0]);
	}
}

public class Main {
	static void cetak(String[] arr) {
		if (arr == null) {
			System.out.println("null");
		}
		else {
			System.out.println(Arrays.toString(arr));
		}
	}
	
	public static void main(String[] args) {
		Kamus kamus = new Kamus();
		kamus.tambah("big", new String[]{"large", "great"});
		kamus.tambah("big", new String[]{"huge", "fat"});
		kamus.tambah("huge", new String[]{"enormous", "gigantic"});
		
		cetak(kamus.ambilSinonim("big"));
		cetak(kamus.ambilSinonim("huge"));
		cetak(kamus.ambilSinonim("gigantic"));
		cetak(kamus.ambilSinonim("colosal"));
	}
}