H1b, H4, H4 EAD extension

[rkalsulkar]

Hi,

I am applying for H1b extension. Along with my H1b, I am applying for my wife's H4, H4 EAD extension. In I 765 for H4EAD, there is space for H1b receipt number for the category of H4 EAD. As I am applying for all of these together, I do not have my receipt number. Has anyone applied for extension yet, and know what is to be filled there?
Please let me know.

Thank you very much for the help.