A gang high jacked the plane which was carrying 200 passengers in it. All the kidnapped passengers were locked in a room. One day, the chief of gang told to all 200 passengers that, "Tomorrow, I am going to execute you all one by one. I am going to make you all stand in a row and going to put a hat on all of your heads which are either Black or White. Every person will be able to see all hats ahead of him but not what is on his own head or behind him. You can only shout White or Black. If you guess the color of your hat right, you will be saved otherwise executed. I will start from last person in a row" and then he left. Scared passengers have one whole night to prepare a strategy so that minimum of them will get executed. Can you guess the strategy ?