What is the first name of the person who stopped Lennon from hammering a nail into the clean board?  Answer the above question based on the context below:  Lennon first met Yoko Ono on 9 November 1966 at the Indica Gallery in London, where Ono was preparing her conceptual art exhibit. They were introduced by gallery owner John Dunbar. Lennon was intrigued by Ono's "Hammer A Nail": patrons hammered a nail into a wooden board, creating the art piece. Although the exhibition had not yet begun, Lennon wanted to hammer a nail into the clean board, but Ono stopped him. Dunbar asked her, "Don't you know who this is? He's a millionaire! He might buy it." Ono had supposedly not heard of the Beatles, but relented on condition that Lennon pay her five shillings, to which Lennon replied, "I'll give you an imaginary five shillings and hammer an imaginary nail in." Ono subsequently related that Lennon had taken a bite out of the apple on display in her work Apple, much to her fury.Ono began to telephone and visit Lennon at his home. When Cynthia asked him for an explanation, Lennon explained that Ono was only trying to obtain money for her "avant-garde bullshit". While his wife was on holiday in Greece in May 1968, Lennon invited Ono to visit. They spent the night recording what would become the Two Virgins album, after which, he said, they "made love at dawn". When Lennon's wife returned home she found Ono wearing her bathrobe and drinking tea with Lennon who simply said, "Oh, hi." Ono became pregnant in 1968 and miscarried a male child on 21 November 1968, a few weeks after Lennon's divorce from Cynthia was granted.Two years before the Beatles disbanded, Lennon and Ono began public protests against the Vietnam War. They were married in Gibraltar on 20 March 1969, and spent their honeymoon at the Hilton Amsterdam, campaigning with a week-long Bed-In for Peace. They planned another Bed-In in the United States but were denied entry, so they held one instead at the Queen Elizabeth Hotel in Montreal, where they recorded "Give Peace a Chance". They often combined advocacy with performance art, as in their "Bagism", first introduced during a Vienna press conference. Lennon...
Yoko