Is the given language finite or infinite?
(0 U 1)((0 U 1)^p)((0 U 1)^p)(0U1))  is not a language, but a regular expression. Moreover, to be well-defined, you must specify what $p$ is.

Is $p$ a specific value?  Then, this expression generates a finite number of words -> it generates a finite language.

But maybe you look at the language generated by the above expression for any p? then, there will be infinitely many generated words.  

you need to tell us what is $p$ and what is the language under consideration.