 Complete the following phrase:  Following the failure of Focus, in September 1983, Irving for the first time attended a conference of the IHR. Van Pelt has argued that, with the failure of Irvings political career, he felt freer to associate with Holocaust deniers. At the conference, Irving did not deny the Holocaust, but did appear happy to share the stage with Robert Faurisson and Judge Wilhelm Stäglich, and claimed to be impressed with the pseudoscientific allegations of neo-Nazi and Holocaust denier Friedrich Fritz Berg that mass murder using diesel gas fumes at the Operation Reinhard death camps was impossible. At that conference, Irving repeated his claims that Hitler was ignorant of the Holocaust because he was so busy being a soldier. In a speech at that conference, Irving stated: Isnt it right for Tel Aviv to claim now that David Irving is talking nonsense and of course Adolf Hitler must have known about what was going in Auschwitz and Treblinka, and then in the same breath to claim that, of course our beloved Mr. Begin didnt know what was going on in 