This logic works:
*1 Get the number of years divisible by 4
*2 Get the number of years divisible by 100
*3 Get the number of years divisible by 400

num leap days = *1 - *2 + *3

Needs a bit of refactoring.
Refactored:
*1 the same year calculation has been removed. the single check works at the end
*2 the 100 year multiples and 400 year multiples have been moved into a function.
Refactored a bit more:
*1 Moved the month number calls just after reading the inputs
*2 Removed the code that was moving the start year to its nearest multiple of 4
Removed the debug statements.
Submission with ID 12995107: WA