Shampooing after rogaine foam!!!

[aim4hair]

Hi all,
How long should i wait after i apply rogaine foam if i wanna take a shower and shampoo my hair ??
I have a buzz cut and I feel that the foam dries pretty fast and is absorbed to my scalp within couple of minutes. Would shampooing an hour or 2 after the application be ok ? Or it would take out all the benifits

P.S. i only use it once aday.