Finance lease – When rentals are payable in advance

Hello everyone

I am a bit confused about this.. I’m using the Kaplan complete text book.
Finance lease on page 186, test your understanding 2.
In the answer, non-current liabilities is $34,712 (54,712 – 20,000).

Question: why minus 20,000? And is it simply the yearly payments of 20000 or the 20000 carried down in 20X5? and why so?

I would have had $16529 for N.C.L. (54712-38183)

Help will be much appreciated 🙂