What is the best response to I love you?

This is happening for more than a year now. I am talking about numbers with my son.

Whenever my 4 year old son says “I love you”, I ask him back “How much?”.
And he replies with the largest number he knows or understands.

It started with 2, 3, 10, 20…
The answer stayed at 42 for a few days… and now he always replies: TRILLIONS.

Still to reach: INFINITY