Question: What son of Grand Duke Lithuania Kęstutis went on to defeat Švitrigaila and his Livonian allies?
{'answer': 'Sigismund Kęstutaitis', 'supporting_facts': [['Battle of Wilkomierz', 1], ['Sigismund Kęstutaitis', 0], ['Sigismund Kęstutaitis', 2]]}