A Tiny Queue with Capacity Two

A queue length process lives on $\{0,1,2\}$. From state $0$ it stays at $0$ with probability $1-a$ and moves to $1$ with probability $a$. From state $1$ it moves to $2$ with probability $a$, to $0$ with probability $b$, and stays with probability $1-a-b$. From state $2$ it moves to $1$ with probability $b$ and stays at $2$ with probability $1-b$. Find the stationary distribution.