Vim: copy/paste in vim command line mode

Update to the downvotes received
I have actually made efforts, spent the entire day figuring out the problem but still couldn't find it. I know I can paste in the editor using the p or P command but don't know how I can paste in the command line itself. I genuinely need help.

I am on Ubuntu 20.04. I have my text copied in my system's clipboard. Now I want to paste the input in vim's command line. I am working on my C++ code which takes in the input. Now I need to paste the input from my system's clipboard to vim's command line.

Below is a screenshot of vim's command line .After hitting enter my C++ code asks for the input which I want to paste from my systems clipboard.

Input to paste

3
10 20 30 0 29 30
0 0 0 0 0 1
1 1 1 0 0 0