Complex sentence: At least 14 were shot down by Armenian air-defences, out of the total inventory of 18 L-29s; the Azeri Air Force lost large amounts of its air force due to anti aircraft fire.
Split into simpler sentences: At least 14 were shot down by Armenian air-defences, out of the total inventory of 18 L-29s. The Azeri Air Force lost large amounts of its air force due to anti aircraft fire.