Jimmy Carter said, "in many countries around the world – my wife and I have visited about 125 countries– you hear John Lennon's song 'Imagine' used almost equally with national anthems." On 9 October 2010, which would have been Lennon's 70th birthday, the Liverpool Singing Choir performed "Imagine" along with other Lennon songs at the unveiling of the John Lennon Peace Monument in Chavasse Park, Liverpool, England. Beatles producer George Martin praised Lennon's solo work, singling out the composition: "My favourite song of all was 'Imagine'". Music critic Paul Du Noyer described "Imagine" as Lennon's "most revered" post-Beatles song. Authors Ben Urish and Ken Bielen called it "the most subversive pop song recorded to achieve classic status". Fricke commented: "'Imagine' is a subtly contentious song, Lennon's greatest combined achievement as a balladeer and agitator."Urish and Bielen criticised the song's instrumental music as overly sentimental and melodramatic, comparing it to the music of the pre-rock era and describing the vocal melody as understated. According to Blaney, Lennon's lyrics describe hypothetical possibilities that offer no practical solutions; lyrics that are at times nebulous and contradictory, asking the listener to abandon political systems while encouraging one similar to communism. Author Chris Ingham indicated the hypocrisy in Lennon, the millionaire rock star living in a mansion, encouraging listeners to imagine living their lives without possessions. Others argue that Lennon intended the song's lyrics to inspire listeners to imagine if the world could live without possessions, not as an explicit call to give them up. Blaney commented: "Lennon knew he had nothing concrete to offer, so instead he offers a dream, a concept to be built upon."Blaney considered the song to be "riddled with contradictions. Its hymn-like setting sits uncomfortably alongside its author's plea for us to envision a world without religion." Urish and Bielen described Lennon's "dream world" without a heaven or hell as a call to "make the best world we can here and now, since this is all this is or will be". In their opinion, "because we are asked merely to imagine – to play a 'what if' game, Lennon can escape the harshest criticisms". Former Beatle Ringo Starr defended the song's lyrics during a 1981 interview with Barbara Walters, stating: "[Lennon] said 'imagine', that's all. Just imagine it."The morning after the November 2015 Paris attacks, German pianist Davide Martello brought a grand piano to the street out in front of the Bataclan, where 89 concertgoers had been shot dead the night before, and performed an instrumental version to honour the victims of the attacks; video of his performance went viral. This led Katy Waldman of Slate to ponder why "Imagine" had become so frequently performed as a response to tragedy. In addition to its general popularity, she noted its musical simplicity, its key of C major, "the plainest and least complicated key, with no sharps or flats" aside from one passage with "a plaintive major seventh chord that allows a tiny bit of E minor into the tonic". That piano part, "gentle as a rocking chair", underpins lyrics that, Waldman says, "belongs to the tradition of hymns or spirituals that visualize a glorious afterlife without prophesizing any immediate end to suffering on earth". This understanding is also compounded by the historical context of Lennon's own violent death, "remind[ing] us that the universe can run ramshod over idealistic people". Ultimately, the song "captures the fragility of our hope after a violent or destructive event ... [bu]t also reveals its tenacity".In June 2017, the National Music Publishers Association awarded "Imagine" a Centennial Song Award and recognized Lennon's desire to add Yoko Ono as a co-author of the song.

Question: What is the first name of the person who was said to be a balladeer and agitator?
Answer: John