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

full_context: Document 1: Junior dos Santos: Junior dos Santos Almeida (] ; born January 30, 1984) is a Brazilian mixed martial artist and a former UFC Heavyweight Champion. As of August 2017, he is #4 in official UFC heavyweight rankings, in addition to being ranked as the #4 heavyweight in the world by Sherdog.
Document 2: Dan Henderson: Daniel Jeffery Henderson (born August 24, 1970) is an American former mixed martial artist and Olympic wrestler, who last competed as a middleweight in the Ultimate Fighting Championship. He was the last Strikeforce Light Heavyweight Champion and was the last Welterweight (80 kg ) and Middleweight (95 kg ) champion of Pride Fighting Championships. Additionally, Henderson was the Brazil Open '97 Tournament Champion, the UFC 17 Middleweight Tournament Champion, the Rings: King of Kings 1999 Tournament Champion and the Pride Weltwerweight Grand Prix Tournament Champion. During his career, Henderson also challenged for the UFC Middleweight Championship (2x), the UFC Light Heavyweight Championship and the Strikeforce Middleweight Championship. He was the first mixed martial artist to concurrently hold two titles in two different weight classes in a major MMA promotion. At the time of his retirement after UFC 204, he was the oldest fighter on the UFC roster. Known to be one of the greatest mixed martial artists of all time having defeated a total of seventeen MMA world champions across four major MMA promotions (UFC, PRIDE FC, Strikeforce, and RINGS).
Document 3: Vitor Belfort: Vitor Vieira Belfort (] ; born April 1, 1977) is a Brazilian mixed martial artist currently competing in the Middleweight division of the Ultimate Fighting Championship. He is the former UFC Light Heavyweight Champion, UFC 12 Heavyweight Tournament Champion, and the Cage Rage World Light Heavyweight Champion. As of June 16, 2017, he is the #11 contender in official UFC Middleweight rankings.
Document 4: Tim Sylvia: Timothy Deane Sylvia (born March 5, 1976) is a retired American mixed martial arts (MMA) fighter, professional wrestler, and former two-time UFC Heavyweight Champion. He has competed as a Super Heavyweight and Heavyweight. While perhaps best known for competing in the UFC, Sylvia has also competed for Affliction, the International Fighting Championships (IFC), and ONE FC.
Document 5: 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.
Document 6: Silviu Vulc: Silviu Dorin Vulc more commonly known as Silviu Vulc is a Romanian heavyweight mixed martial artist. Silviu Vulc spent his early career boxing in Romania, he then moved to Russia to train with Red Devil Sport Club team mates with Fedor Emelianenko and Alexander Emelianenko. Vulc spent two years there training and fighting. During this time he had ten MMA fights with eight wins and three losses, the first seven fights being semi-professional before moving into the professional league. Vulc had a short professional career, defeating Rodrigo Mendes in the Desert Combat Challenge in Israel and losing twice. His last fight being in 2008 for M-1 Global. Silviu has spent most of his time and energy over the years coaching others in boxing and MMA around the world including time spent in Russia, Romania and London, England.
Document 7: Antônio Rodrigo Nogueira: Antônio Rodrigo Nogueira (] , born June 2, 1976), better known as Minotauro, is a semi-retired Brazilian mixed martial artist known for his technical mastery of Brazilian jiu-jitsu. He won most of his fights via submissions. He competed in the heavyweight division of the Ultimate Fighting Championship (UFC), where he is a former Interim UFC Heavyweight Champion. He is the twin brother of UFC fighter Antônio Rogério Nogueira. Nogueria rose to prominence in the Japanese promotion Pride Fighting Championships, where he was the first Pride Heavyweight Champion from November 2001 to March 2003, as well as a 2004 PRIDE FC Heavyweight Grand Prix Finalist. He is one of only three men to have held championship titles in both Pride Fighting Championships and the Ultimate Fighting Championship (the others being Mauricio Rua and Mark Coleman).
Document 8: Frank Mir: Francisco Santos "Frank" Mir, III (born May 24, 1979) is an American mixed martial artist, who competes for Bellator MMA in the Heavyweight division. He formerly competed in the Ultimate Fighting Championship (UFC) for sixteen years. A former UFC Heavyweight Champion, he currently holds the record for most fights, victories, and submissions in UFC Heavyweight history, and is tied for 4th most UFC victories overall. Up until his release, Mir possessed the longest uninterrupted tenure of any fighter in UFC history. He is the first man to knock out and submit Antônio Rodrigo Nogueira.
Document 9: Demian Maia: Demian Augusto Maia Baptista (] born November 6, 1977) is a Brazilian mixed martial artist and Brazilian Jiu-Jitsu practitioner. He currently fights as a welterweight for the Ultimate Fighting Championship. As of May 20, 2017, he is #1 in the official UFC welterweight rankings. Maia is regarded as one of the greatest grapplers in MMA history.
Document 10: B.J. Penn: Jay Dee "B.J." Penn (born December 13, 1978) is an American professional mixed martial artist and Brazilian Jiu-Jitsu practitioner. Penn debuted and competed in the Ultimate Fighting Championship (UFC), and later in K-1. Prior to fighting for the UFC, he became the first American Gold medalist of the World Jiu-Jitsu Championship. In mixed martial arts, Penn has competed in the Featherweight, Lightweight, Welterweight, and Middleweight divisions. As a former UFC Lightweight Champion and UFC Welterweight Champion, he is one of only three fighters in UFC history to win titles in multiple weight classes. Penn was also a Co-champion in the UFC 41 Lightweight Tournament, due to an eventual draw opposite Caol Uno in the tournament finale. Through his tenures as champion, Penn unofficially unified the UFC Lightweight Championship (against Sean Sherk) and broke the all-time lightweight title defense record. Penn was inducted into the UFC Hall of Fame, as the inaugural inductee in the Modern-Era Wing by career-long rival Matt Hughes, during "International Fight Week" in July 2015.
Document 11: Anderson Silva: Anderson da Silva (] ; born April 14, 1975) is a Brazilian mixed martial artist and former UFC Middleweight Champion. Silva holds the longest title streak in UFC history, which ended in 2013 after 2,457 days, with 16 consecutive wins and 10 title defenses. He has 13 post-fight bonuses, the second most in UFC history. UFC president Dana White and several mixed-martial-arts publications have called Silva the greatest mixed martial artist of all time. He is currently ranked the #6 contender in official UFC middleweight rankings.
Document 12: Murilo Rua: Murilo "Ninja" Milani Rua (] ; born May 22, 1980) is a retired Brazilian mixed martial artist who fought in Pride Fighting Championships. He is the older brother of former UFC Light Heavyweight Champion Mauricio "Shogun" Rua. He is known for his aggressive Muay Thai style. Rua is a veteran of Pride Fighting Championships, where he once enjoyed a reputation as one of the best middleweights in the world. Rua regularly fought at 185 pounds, but has also fought at 205 pounds and heavyweight. He is the former (and first ever) EliteXC Middleweight Champion. He also had a successful career in mixed martial arts in England appearing on both Cage Rage and BAMMA cards. He is of Portuguese and Italian descent, but was born in Brazil.
Document 13: 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.
Document 14: Renato Sobral: Renato da Cunha Sobral (] ; born September 7, 1975), also known as "Babalu", is a retired Brazilian wrestler and mixed martial artist, and former Strikeforce Light Heavyweight Champion. Sobral previously fought in the Ultimate Fighting Championship, where he posted a 6–4 record and has also competed for Bellator, RINGS, Jungle Fight, Cage Rage, Affliction, and ONE FC. He is the Head Instructor of Babalu's Iron Gym Cerritos and has a Luta Livre black belt. He is also a Brazilian jiu-jitsu black belt under Carlos Gracie Jr. In his prime he was considered one of the top fighters in the world and defeated the likes of former Welterweight UFC Champion Robbie Lawler, former Light Heavyweight UFC Champion Shogun Rua, former Heavyweight UFC Champion Maurice Smith, along with former title contenders Chael Sonnen, Elvis Sinosic, and Jeremy Horn.
Document 15: José Aldo: José Aldo da Silva Oliveira Junior (] ; born September 9, 1986) is a Brazilian mixed martial artist in the Ultimate Fighting Championship. He was the fourth and final WEC Featherweight Champion and thus, became the first UFC Featherweight Champion during the UFC/WEC merger. He is a former two-time UFC Featherweight Champion. He was named Sherdog's 2009 Fighter of the Year. He is currently #12 in official UFC pound-for-pound rankings, having been ranked as high as #1 in 2015, and ranked the #2 featherweight in the world and #7 pound-for-pound by Sherdog. In the decade from November 2005 through December 2015, Aldo was undefeated in 18 fights. In Sherdog's April 2017 Pound-For-Pound ranking, Aldo was called "the greatest featherweight in mixed martial arts history."
ground_truth: Brazilian