Task: Question Answering
Input (English): Passage: In an opening scene before the credits, an assassin, Banat, is seen preparing a gun while a gramophone skips as it plays. The story that follows is the narrative of a letter from Howard Graham, an American armaments engineer, to his wife Stephanie. While journeying to the Soviet port of Batumi to return to the United States to complete his business with the Turkish Navy, Graham and his wife stop in Istanbul and are met by Kopeikin, a Turkish employee of Graham's company, who under the pretense of discussing business, takes Graham to a nightclub to introduce him to dancer Josette Maretl and her partner Gogo. Banat tries unsuccessfully to kill Graham during a magic act, shooting the magician instead. Graham is brought to the headquarters of the Turkish secret police for questioning, where Colonel Haki blames the assassination attempt on German agents seeking to delay the re-arming of Turkish ships. The colonel shows Graham a photograph of Banat, who he says was hired by a Nazi agent named Muller. Haki then orders Graham to travel secretly to Batumi aboard a tramp steamer, while Haki personally oversees the safe overland transit of Stephanie.

Graham's fellow passengers include Josette and Gogo; Kuvetli, an ingratiating Turkish tobacco salesman; Professor Haller, an apolitical German archeologist; and the henpecked Matthews and his French wife. Josette sees that Graham is frightened, and not knowing that he is married, tries to become close to him. At an interim port call, Graham is made aware of the arrival of a new passenger by the annoying clamor of a gramophone, while Haller warns him that Kuvetli is not who he claims to be. At dinner Graham recognizes Banat and tries to persuade the ship's captain and purser to put him ashore, but they believe that he is crazy. Graham turns to Josette for help and she has Gogo engage Banat in a poker game while Graham unsuccessfully searches Banat's cabin for the assassin's gun. 
Question: What is the first name of the person that the German archeologist warns?
Output (English): Howard.