Definition: In this task, you're given a question, along with a context passage which has extra information available on certain terms mentioned in it, i.e., the proper nouns in the passage. Your job is to determine whether information from more than one term is needed to answer the question. Indicate your choice as `a` for Yes or `b` for No.
Input: Question: Which ruler that Charlemagne allied with ruled for a longer period of time? Passage:Since about 560, the Avars had ruled over large parts of the Pannonian Basin and Carantania southeast of Francia, though in the last decades, the Avar Khaganate had to deal with Bulgarian and Croat incursions. To secure the frontier of his empire and the traffic on the trade routes to the east, Charlemagne allied with Khan Krum of Bulgaria and the Croatian duke Vojnomir, and from 791 launched several campaigns against the Avars, where he, according to the Vita Karoli Magni, encountered only modest opposition. In 796 Carolingian forces under Charlemagne's son Pepin of Italy destroyed the main Avar fortress called the Ring of the Avars and made the Khagan a Frankish vassal, while the remaining Avars retreated behind the Tisza River. The victory is perpetuated by the poem De Pippini regis Victoria Avarica. 


a