Well, the title says it all. How are we supposed to start this?
I have calculated a recurrence relation for this $E(n, m)=\frac{4}{6}(1+E(n, m))+\frac{1}{6}(1+E(n-1, m))+\frac{1}{6}(1+E(n, m-1))$.
Is this the correct way and is there a better way to solve this?