There are n ≥ 3 friends sitting in a circle around a campfire, each with

exactly one s'more. The friends then decide to exchange their s'mores.

Each individual faces the following decision, independent of the others:

with probability 1/3, he passes his s'more to the person to his left, and

with probability 2/3, he passes his s'more to the person to his right.

What is the expected number of people that will end up with no s'more?

Please begin by describing the probability space.