Question: Former MMA champions Antonio Silva and Fabricio Werdum are both what South American nationality?

Context paragraphs:
Mandi Urbas: Hermann 'Mandi' Urbas (born 18 June 1982) is a former professional footballer with dual German and American nationality.

United States nationality law: The United States nationality law is a uniform rule of naturalization of the United States set out in the Immigration and Nationality Act of 1952, enacted under the power of Article I, section 8, clause 4 of the United States Constitution (also referred to as the Nationality Clause), which reads: Congress shall power - "To establish a uniform Rule of Naturalization..." The 1952 Act sets forth the legal requirements for the acquisition of, and divestiture from, American nationality.  The requirements have become more explicit since the ratification of the Fourteenth Amendment to the Constitution, with the most recent changes to the law having been made by Congress in 2001.

Pancrase: Yes, We Are Hybrid Wrestlers 1: Pancrase: Yes, We Are Hybrid Wrestlers 1 was the first mixed martial arts event held by Pancrase Hybrid Wrestling.  It took place at the Tokyo Bay NK Hall in Urayasu, Chiba, Japan on September 21, 1993.  The card featured many future MMA champions.

Championship Fighting Alliance: Championship Fighting Alliance (CFA) is a mixed martial arts (MMA) based promotion company located in Miami Lakes, Florida.  It was founded by former MMA fighter and promoter Jorge De La Noval in 2011.  It has currently produced 10 live events.  Fallon Fox, who currently is signed to fight for CFA, is the first openly transgender MMA fighter in history.  On May 24, 2013, CFA will be hosting CFA 11, their 11th event at the Bankunited Center located on the University of Miami campus.  Fighter 411 reported that CFA had held the most events in Florida during the 2012-2013 season.

Ranik Ultimate Fighting Federation: Ranik Ultimate Fighting Federation (RUFF) is the first Chinese mixed martial arts (MMA) organization sanctioned by the General Administration of Sport of China.  The winners of the title fights will be crowned as the national MMA champions of China in their respective weight classes.  RUFF held its first event in August 2011 in Shanghai, before presenting in Chongqing, Hohhot, Nanjing, and Sanya.  In February 2013 RUFF awarded Championship belts in five weight classes, at their Superfight event.  Together with the Championship belt, each winner was awarded 1,000,000 RMB.  RUFF along with Mandt Bros.  Productions produced and aired a 10 episode reality series "RUFF: Journey" leading up to the Superfight.  A new episode will air each week and will be nationally televised across China with TV viewership of over 30 million, over 10 episodes.

Fabrício Werdum: Fabrício Werdum (] ; born July 30, 1977) is a Brazilian mixed martial artist and former UFC Heavyweight Champion.  He is also a two-time Brazilian jiu-jitsu world champion, a two-time Abu Dhabi Combat Club World Heavyweight Champion and European jiu-jitsu champion.  He holds black belts in Brazilian jiu-jitsu, Judo, and Muay Thai.  Werdum has competed in PRIDE, the UFC, Strikeforce, and Jungle Fight.

Antônio Silva (fighter): Antônio Carlos Silva (born September 14, 1979) is a Brazilian mixed martial artist who formerly competed in the heavyweight division of the UFC.  He is a former EliteXC Heavyweight Champion, a former Cage Rage World Heavyweight Champion and a former Cage Warriors Super Heavyweight Champion.  He has also competed for K-1 Hero's, BodogFIGHT, Strikeforce and World Victory Road.  Known for being one of the five men (along with Tsuyoshi Kohsaka, Fabrício Werdum, Dan Henderson, and Matt Mitrione) to defeat Fedor Emelianenko in mixed martial arts competition.

Yushin Okami: Yushin Okami (岡見 勇信 , Okami Yūshin , born July 21, 1981) is a Japanese mixed martial artist currently competing in the Light Heavyweight division of the UFC.  A professional competitor since 2002, Okami has also formerly competed for PRIDE, Pancrase, M-1 Global, World Series of Fighting, and Professional Fighters League.  He holds notable wins over Mark Munoz, Hector Lombard, Alan Belcher (twice),Anderson Silva (Via DQ), Nate Marquardt, former MMA fighter Evan Tanner and Mike Swick.

DJ Marky: Marco Antonio Silva a.k.a. DJ Marky is a Brazilian drum and bass DJ.

List of American film actresses: This is an alphabetical list of notable American film actresses.  It contains both actresses born American and those who acquired American nationality later.

Supporting paragraphs: Antônio Silva (fighter) Fabrício Werdum
Answer: Brazilian