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: Who wrote the letters that stated Nubian fighting men were sought after by kingdoms in Southwest Asia? Passage:During the Middle Kingdom military sophistication and strength continued to expand. Well-organized expeditions into Nubia were conducted, and a number of fortresses were built to control Nubian territory, such as the works at Buhen. Deep ditches surrounded some of these fortifications, with walls up to 24 feet thick, creating strong bases against rebellion or invasion. Recruiting quotas were assigned on a regional basis and designated scribes drafted soldiers as needed for the armies of the state. Striking forces were still primarily infantry-based, and tactics did not change drastically from previous eras. A key role in the strengthening of Egyptian forces was played by infantrymen from Nubia, both as spearmen and archers. Parts of Nubia were renowned for such fighting men, and indeed a part of the Nubian territory was called Ta-Seti or Land of the Bow by the Egyptians. The Egyptians and Nubians were ethnically the closest in the region, frequently exchanging people, genes, resources and culture over several centuries, and occasionally engaging one another in military conflict. Nubian fighting men were also sought as mercenaries by various kingdoms of Southwest Asia, according to the Amarna letters.


b