Given a document, find the main entity about whom the author is writing. Write the full name if mentioned in the text. Note that URLs in the text have been replaced with [Link].

Input: Consider Input: Sen. Bob Corker (R-TN)  speaks with reporters after announcing  his  retirement at the conclusion of  his  term on Capitol Hill in Washington  U.S.  September 26  2017. REUTERS/Aaron P. Bernstein
WASHINGTON (Reuters)  - U.S. Senator Bob Corker   the influential Republican chairman of the Senate Foreign Relations Committee  said on Tuesday he will not run for re-election  a blow to a party already struggling to balance divisions between mainstream and more populist wings.
An establishment Republican   Corker  has been criticized from the right  and a conservative activist had already announced a primary challenge. But he was expected to keep the seat  and had amassed a $7.5 million campaign war chest.
 Corker  has ruled out running for governor of Tennessee.
âI have no idea what Iâm going to do. No idea whatsoever â  Corker  said in an interview. But he said he was not leaving out of frustration over deep party divides that have often paralyzed Congress.
 Corker  announced  his  retirement on the day of the failure of the latest Republican effort to repeal former Democratic President Barack Obamaâs healthcare law.
âI am not going to be one of the people who leaves here badmouthing what is one of the greatest privileges of oneâs life â  Corker  said.
He said he realized he was ready to retire on Aug. 24 during a factory groundbreaking in Clarksville  Tennessee  and almost announced his decision at least twice before Tuesday.  Corker  said that he made his announcement now to allow a strong candidate time to enter the Senate race.
 Corker  is the first senator to announce  his  retirement ahead of the 2018 mid-term elections  when one-third of the 100-seat chamber will be up for grabs. Tennessee is a solidly Republican state and the party  which currently holds a 52-seat majority in the Senate  is favored to keep his seat.
In his official announcement   Corker  said that âafter much thought  consideration and family discussionâ over the past year  he and his wife Elizabeth âhave decided that I will leave the United States Senate when my term expires at the end of 2018.â
 Sen. Bob Corker (R-TN)  walks away after speaking with reporters after announcing  his  retirement at the conclusion of  his  term on Capitol Hill in Washington  U.S.  September 26  2017. REUTERS/Aaron P. Bernstein
CLASHES WITH  TRUMP
In August  after Trumpâs much-criticized reaction to violence at a white supremacist rally in Virginia   Corker  told reporters in  his  home state Tennessee that Trump had not been able to demonstrate the âstabilityâ or competence that  he  needed to be successful as president.
After the exchange  the two men had an hour-long meeting at the White House this month that  Corker  has described as a wide-ranging and friendly discussion.
 Corker  will remain chairman of the Foreign Relations Committee until he leaves in January 2019. He said he wanted the panel to address issues including Secretary of State Rex Tillersonâs State Department reorganization  food aid reform  and the fight against human trafficking and modern slavery.
 Corker  said the committee would address the international nuclear agreement with Iran  as Trump faces a mid-October deadline for deciding whether to certify that Tehran is complying with that pact. That decision could force Congress to decide whether to reimpose sanctions.  Corker  would not say whether Trump had decided to certify or not.

Output: Bob Corker


Input: Consider Input: Taylor Swift  seen on the streets of Manhattan on September 7  2016 in New York City.
 Taylor Swift  seen on the streets of Manhattan on September 7  2016 in New York City. James DevaneyâGC Images
 Taylor Swift  might just have met  her  biggest fan yet â and pulled off one of  her  biggest surprises while  she  was at it.
Lara didnât seem to hear her  continuing to express her gratitude to  Swift   crying through tears to say: âI have to say thank you for everything  youâve actually made my life so much better.â

Output: Taylor Swift


Input: Consider Input: CES is in full swing  and there is a particular buzz about the intersection of tech and healthcare through a very unexpected source in  best-selling author John Grisham (The Firm  The Client) .  Grisham  is applying  his  enviable skills to the powerful intersection of tech and healthcare and potentially about to turn it on its ear.
 Grisham  spoke from one of the CES stages about the growing public interest to  his  recent ebook  The Tumor which describes how a revolutionary  new medical technology called focused ultrasound could transform the treatment of serious medical disorders by curing with sound. The fictional story follows the plight of a young father who is diagnosed with a lethal brain tumor and begins a painful battle. Yet the treatment method and the tech behind it is not only very real but something which with  Grisham  is now deeply involved.  He  gave a candid interview about the scope of  his  work with this potentially game-changing move in healthcare  along with Dr. Neal Kassell  founder and chairman of the Focused Ultrasound Foundation (FUSF) and a former neurosurgeon who provided the medical and technical consulting for the book.
Prior to taking the stage at CES Grisham told me that Kassell approached  him  about being on the board of FUSF but that respectfully declined  several times. "Prior to my current involvement  I knew essentially nothing about the medical field. My usual focus is on legal matters and social injustice. So I was lukewarm  to say the least "  Grisham  said. However  as both  his  mother and  his  sister were diagnosed with cancerous tumors   he  began to see how the research that FUSF does could help millions of people facing the same diagnosis worldwide. FUSF's mission is to bring the technology that enables a lower cost method to destroy tumors with out-patient  ultrasound options and eradicate such terminal illness  where possible. Naturally  such continued research and development of this technology is expensive.
"So as I was on the board  I thought one of the best ways I could help would be to raise money "  Grisham  explained. FUSF has an annual operating budget of $10 million with 65% of that needed for research  itself. "We needed to raise awareness. Naturally  you do that through telling a story. I know how to do that." So  he  began to work with Kassell to write The Tumor with Kassell providing the deeply medical insights. After about a year  the book was ready and the Foundation it published. They decided to offer it for free and Jeff Bezos CEO of Amazon permitted them to distribute the book via the platform at this price point given its link to social good.


Output: John Grisham