By Krisztina Than and Anna Wlodarczak-Semczuk TISZABEC, Hungary/WARSAW (Reuters) – Poland sought to ease passage into the European Union on Monday for around quarter of a million Ukrainians waiting at European border crossings in freezing conditions after fleeing the Russian invasion of their country. With men of conscription age prevented from leaving Ukraine, groups of mainly women and children arrived at borders in eastern Poland, Slovakia and Hungary and in northern and northeastern Romania. Wait times to cross borders ranged from a few hours at small crossings to several days at busier on…