There is not enough information to answer this. What is "Lecture 8 slide 18 and 19"? If you ask a question at least provide the full context. As is, nobody will be able to answer this for you.
Take the first four characters of your surname - this is your dog name. Now, using the mapping suggested in Lecture 8 (slides 18 and 19), work out your collar number.
For example
"My dog name is LEVI and my collar number is 214873"
I want to know the method how it find.
How to find collar number in python