Unique number from random integers

So I made a discord bot using python and there is a command that have as input two mentions and as output a random number between 1 and 8.

What I want to do is to make a result unique. For example we can convert the two mentions as numbers using users ids. And then find a formula or a way that the two ids will convert in a random number between 1 and 8 but that will always be the same. Every time we mention the two same users I want the same result. I don’t know if it’s possible with a formula or it will require to store some data. Of course I prefer a way that doesn’t require to store data.

Is it possible to do something like this ?