Good afternoon, I'm having trouble solving this problem of stochastic process in continuous time markov chains. Do you know how to solve?

Problem:

Suppose S frogs play in a lake. When they are in the sun, they jump into the lake with rate = 1. When they are in the water, they jump into the sun with rate = 2. Be Xt the number of frogs in the sun in time t. Write matrix Q of this process. How to show that the stationary distribution is Binomial.

Thanks.