You can find many articles on the Internet about how to identify a leap year. microsoft.com, wikipedia.org, earthsky.org
However, this is not a frequently used pointer. Maybe someone's going to use the prepared equation:
I will not work without coffee.
Transparent 1. element:
Transparent 2. element:
Place element 2 under element1.
Element 2 is visible whenever the year is divisible 4, but is not divisible by 100.
Element 1 solves the exception by dividing 400.
Thanks and sorry for confusion