As per my understanding H1B is issued in 3+3 year format. My H1B petition was approved (didnt get stamped) in Dec/2016 and it has expiry date Sep/2019. I never used it so far and I never went to the USA on it. So, If I move to the USA and start working for my employer from Aug 2018, how many years I can work for? Would I get all 6 years(3+3) the day I enter the USA or have I lost my h1 time from Dec 2016 to July 2018?