How to PICK the CTRL-u argument from the file or some other method, with EXAMPLE

[jose@Aumara.zzn.com (Jose Cuthberto)]

An example would clarify the problem:

Suppose you want to paste a single killed line (in kill buffer using two C-k's)
you can trivially do it like this:

C-u 2 C-y

In this case you had to enter the numbers.

I have a file like this:

5
line1
6
line2

Now I must convert it to a file with 5 line1's and 6 line2's and so on.
It is a long file.

How do I pick 5 and put it into C-u so that it is done 5 times.

I can write macros. and I can also write single line lisp functions.
Unfortunately there is no yank cammand that can take the argument 5.
nor do i know the lisp function that can take the count and pass it to 
lisp function yank. I would want to avoid writing a loops, and vars etc.

Thanks to the star who can help!!!

jose