It can be simplified as a probability event in which six people draw a ticket.
The first person draws 1/6, and 5/6 fails.
The second person draws in two ways.
The first person who can't draw it is: (5/6)*( 1/5)= 1/6.
That is, the product of the probability that the first person can't draw and the probability that the remaining five people can draw.
If the first person smokes, the probability of the second person smoking is 0.
By analogy, the probability is 1/6.
This is an equal probability event.