Which of these actors has won the most Academy Awards for Best Actor?

Jack Nicholson (born April 22, 1937) is an American retired actor and filmmaker. He is widely regarded as one of the greatest actors of all time. He received numerous accolades throughout his career which spanned over five decades, including three Academy Awards, three BAFTA Awards, six Golden Globe Awards, a Grammy Award, and a Screen Actors Guild Award. Nicholson has won three Academy Awards, for Best Actor for One Flew Over the Cuckoo's Nest (1975) and As Good as It Gets (1997) and for Best Supporting Actor for Terms of Endearment (1983). Meanwhile, Robert De Niro, Leonardo DiCaprio, and Denzel Washington have only won one Oscar for Best Actor.

Source: Movie web