Could you help me to respond this email in an appropriate and polite way?
I send an email to a professor and asked him about available PhD positions. He responded to my email as:
Dear Faisal:

Unfortunately, I am not accepting any new students in preparation for my retirement.

With best wishes,
Rama Bhat

Now I'd like to respond to him in a polite way. I'd like to say that although I'm sad about that he can't accept me, I really appreciate his quick response.
Thank you for your helps in advance.

Question

Could you help me to respond this email in an appropriate and polite way?
I send an email to a professor and asked him about available PhD positions. He responded to my email as:
Dear Faisal:

Unfortunately, I am not accepting any new students in preparation for my retirement.

With best wishes,
Rama Bhat

Now I'd like to respond to him in a polite way. I'd like to say that although I'm sad about that he can't accept me, I really appreciate his quick response.
 Thank you for your helps in advance.

Answer

Dear Professor Bhat:

I very much appreciate your quick response.

I had very much wanted to be one of your students.

I wish you,  sir, a very happy and productive retirement.

Sincerely yours,

Faisal  [last name]

Answer

All you need to do is use "the fact,"  before the "that," in your own message and then you have answered your own question.

You might want to add a wish for a happy retirement.

Why not have a go at writing something yourself, and then post it in the corrections thread (Notebook)?