sentence1: Alla Petrovna Tsuper ( born April 16 , 1979 ) is a Ukrainian cross-country skier ( until 2000 ) and a Belarusian ( since 2000 ) .
sentence2: Alla Petrovna Tsuper ( born 16 April 1979 ) is a Belarusian ( until 2000 ) and Ukrainian ( since 2000 ) aerial skier .