You will be given a definition of a task first, then some input of the task.
Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.

Passage: The two most prominent Norman families to arrive in the Mediterranean were descendants of Tancred of Hauteville and the Drengot family, of whom Rainulf Drengot received the county of Aversa, the first Norman toehold in the south, from Duke Sergius IV of Naples in 1030. The Hauteville family achieved princely rank by proclaiming prince Guaimar IV of Salerno 'Duke of Apulia and Calabria'. He promptly awarded their elected leader, William Iron Arm, with the title of count in his capital of Melfi. The Drengot family thereafter attained the principality of Capua, and emperor Henry III legally ennobled the Hauteville leader, Drogo, as 'dux et magister Italiae comesque Normannorum totius Apuliae et Calabriae' ('Duke and Master of Italy and Count of the Normans of all Apulia and Calabria') in 1047. Question: Who was Count of Melfi
Output:
William Iron Arm