How to automatically change the name of a file on a daily basis

I am new to Linux/CentOS and right now I am running into a little problem.

My CentOS7 Server logs all Maillogs, via Logrotate, on a daily basis and moves them to the folder /var/log/old_maillogs. Right now the logs are saved with a name similar to this:

Maillog-20230721

I would like their names to change, based on how old they are, so that if the Log is one day old it's named:

Maillog-1

And one the day after that, the files name changes to:

Maillog-2

And so on.

Is this even possible, if so, what would be the smartest way to get it working? I have read a lot about scripts that get executed once per day, but then again, how do I code the script, so that it recognizes how many logs are in the folder?

This is my current config:

/var/log/maillog{

daily

rotate 365

postrotate

   Systemctl restart rsyslog.service

endscript

mailfirst

olddi /var/log/old_maillog

}

As @asktyagi already stated. The right parameter to use is "start count".

Initially it didn't work for me, that's because I didn't disable the parameter for "use data extension for rotated files", which is called nodateext.

So the working config looks like this:

/var/log/maillog{

daily

rotate 365

postrotate

   Systemctl restart rsyslog.service

endscript

mailfirst

olddi /var/log/old_maillog

start 1

nodateext
}

This config saves logs on a daily basis and renames the extension to the number, that is equivalent to how old the log is.

So on day 1 it's called - maillog.1

And on day 2 it's called - maillog.2

And so on.