Alien GoHome

Since the Earth is seriously polluted, the Aliens who immigrated to there must go home. There are total 7 Aliens and 1 Robot, but have a 2-seated spaceship only.

Instructions:
>> 3 groups of Aliens : RED, GREEN & BLUE
>> the ROBOT belongs to the Red team
>> only the Leader of each group can control the spaceship
>> the ROBOT will be destroyed by the others if the Red team’s Leader not accompanying
>> the Aliens will be attacked by the other teams’ Leader if their own team Leader is not around
>> all the aliens from different teams and the robot need to go home safely
>> a single flight is counted as one round
>> use minimum rounds to rescue them