You are given a mission by God to be a saint who will determine the true gates to the Heaven among "n" gates, numbered from 1 to "n".
Some gates lead to the Heaven and some gates lead to the Hell.
We do not know how many and which gate leads to where!
People come to these gates with the "tickets" and give them to the "guardians" beside
these gates. You do not and can not know what is written on the ticket!
The guardian at the gate you choose checks the ticket and then tells you the destination of the gate.
Of course you are free to take the gate or not. 
You can try another gate with another guardian.
Some guardians are liars and some are honest ones. We do not know which is an honest one or a liar.
The honest one changes your destination on the ticket and tells you your new true destination. 
Liars don't change anything yet tell you lies! That is you think your 
destination is to the Heaven while you can go to the Hell! 


Propose a way to determine liars and honest guys plus to have a ticket
to the Heaven (the final true destination). You can also look at some kind of 
complexity analysis stuff based on the "n". You can philosophize on the problem,
about the number of gates, the existence of liars and honest ones... etc. 
Any extension is welcome...


 Hint:
 
 When the angel of kindness saw that you are given this mission, she started to sing:


    " One after another
      I searched them
      Answers came like waves
      Bringing me
      Persistence of lies
      and the caprice of the truth."


Good luck!