Random walk in unit cube in $\mathbb R^3$

Let us consider a random walk on the vertices of the unit cube in $\mathbb R^3$ .

it is the
Markov chain for which, at each step, the chain moves from a vertex to one of the three
adjoining vertices with probability $\frac{1}{3}$ Let us fix one of the vertices,
a , and let T be the hitting time in F ={a}
- a =  Wheat \

What is the average distance that an ant will walk until it reaches Wheat?