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 was in power longer, Radu I or Dan I? Passage:There is evidence that the Second Bulgarian Empire ruled at least nominally the Wallachian lands up to the Rucăr–Bran corridor as late as the late 14th century. In a charter by Radu I, the Wallachian voivode requests that tsar Ivan Alexander of Bulgaria order his customs officers at Rucăr and the Dâmboviţa River bridge to collect tax following the law. The presence of Bulgarian customs officers at the Carpathians indicates a Bulgarian suzerainty over those lands, though Radu's imperative tone hints at a strong and increasing Wallachian autonomy. Under Radu I and his successor Dan I, the realms in Transylvania and Severin continued to be disputed with Hungary. Basarab was succeeded by Nicholas Alexander, followed by Vladislav I. Vladislav attacked Transylvania after Louis I occupied lands south of the Danube, conceded to recognize him as overlord in 1368, but rebelled again in the same year; his rule also witnessed the first confrontation between Wallachia and the Ottoman Empire (a battle in which Vladislav was allied with Ivan Shishman). After the Magyar conquest (10-11th century), Transylvania had become an autonomous and multi-ethnic voivodeship led by a voivode appointed by the King of Hungary until the 16th century. Several Kings of Hungary invited settlers from Central and Western Europe, such as the Saxons, to come to Transylvania and occupy the region. The Szeklers were brought to southeastern Transylvania as border guards. Romanians are mentioned by the Hungarian documents (township called Olahteluk) in the 13th century (1283) in Bihar County. The "land of Romanians" (Terram Blacorum) appeared in Fogaras, and this area was mentioned under the name "Olachi" in 1285. After the collapse of the Hungarian Kingdom (following the disastrous Battle of Mohács, 1526) the region became the independent Principality of Transylvania until 1711.


a