Original: While under interrogation Rudolf Hoess, commandant of Auschwitz concentration camp from 1940 to 1943,Wikipedia:Rudolf Hoess said that Adolf Eichmann told him that two and a half million Jews had been killed in gas chambers and about half a million died "naturally".
Simplified: Nazi Rudolf Hoess said that between 2.5 and 3 million had been killed, while Adolf Eichmann gave a figure of 2 million.