By Krisztina Than and Alicja Ptak TISZABECS, Hungary/MEDYKA, Poland (Reuters) – Ukrainians arriving into the European Union on Tuesday described their frantic journeys to the border after leaving behind husbands and fathers to fight a Russian invasion and escaping their homes to the sound of shelling. As a massive Russian convoy rumbles toward the Ukrainian capital Kyiv, the United Nations said more than 500,000 refugees had fled to neighbouring countries since Russian President Vladimir Putin launched what he has called “a special military operation” last Thursday. [L1N2V408B] At the Hungaria…