Task: Question Answering
Input (English): Passage: The Night of the Long Knives (German: Nacht der langen Messer ), or the Röhm Purge, also called Operation Hummingbird (German: Unternehmen Kolibri), was a purge that took place in Nazi Germany from June 30 to July 2, 1934, when Adolf Hitler, urged on by Hermann Göring and Heinrich Himmler, carried out a series of political extrajudicial executions intended to consolidate his hold on power in Germany, as well as to alleviate the concerns of the German military about the role of Ernst Röhm and the Sturmabteilung (SA), the Nazis' own mass paramilitary organization. Nazi propaganda presented the murders as a preventive measure against an alleged imminent coup by the SA under Röhm – the so-called Röhm putsch.
The primary instruments of Hitler's action, who carried out most of the killings, were the Schutzstaffel (SS) paramilitary force under Himmler and its Security Service (SD) under Reinhard Heydrich, and the Gestapo, the secret police, under Göring. Göring's personal police battalion also took part in the killings. Many of those killed in the purge were leaders of the SA, the best-known being Röhm himself, the SA's chief of staff and one of Hitler's longtime supporters and allies. Leading members of the leftist-leaning Strasserist faction of the Nazi Party, including its figurehead, Gregor Strasser, were also killed, as were establishment conservatives and anti-Nazis, such as former Chancellor Kurt von Schleicher and Bavarian politician Gustav Ritter von Kahr, who had suppressed Hitler's Munich Beer Hall Putsch in 1923. The murders of SA leaders were also intended to improve the image of the Hitler government with a German public that was increasingly critical of thuggish SA tactics. 
Question: What is the first name of the person who the SA was under during an alleged imminent coup?
Output (English): Ernst.