using System;
using System.Collections.Generic;
 
class Kamus{
    private Dictionary<string, LinkedList<string>> data =
        new Dictionary<string, LinkedList<string>>();
 
    public void tambah(string kata, string[] sinonim){
        if (!data.ContainsKey(kata))
            data[kata] = new LinkedList<string>();
 
        foreach (string s in sinonim){
            data[kata].AddLast(s);
 
            if (!data.ContainsKey(s))
                data[s] = new LinkedList<string>();
 
            data[s].AddLast(kata);
        }
    }
 
    public string[] ambilSinonim(string kata){
        if (data.ContainsKey(kata))
            return new List<string>(data[kata]).ToArray();
 
        return null;
    }
}
 
class Program
{
    static void Main()
    {
        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" });
 
        Console.WriteLine(string.Join(", ", kamus.ambilSinonim("big")));
        Console.WriteLine(string.Join(", ", kamus.ambilSinonim("huge")));
        Console.WriteLine(string.Join(", ", kamus.ambilSinonim("gigantic")));
    }
}