Christian Cyrus Leben (born July 21, 1980) is a retired American mixed martial artist.
 He formerly competed with the UFC as a Middleweight, compiling a record of 12-10 in 22 appearances for the organization.
 Leben first appeared in the inaugural season of "The Ultimate Fighter" reality series, and has also fought in the now-defunct WEC.
 He began his UFC career with five victories in a row before suffering a knockout loss to future UFC Middleweight Champion Anderson Silva.
 Leben was the inaugural WEC Middleweight Champion.
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.
Ronaldo Souza dos Santos (born December 7, 1979), nicknamed Jacaré (] ), is a Brazilian mixed martial artist, submission grappler and Brazilian jiu-jitsu practitioner competing in the UFC's middleweight division.
 Souza is the former Strikeforce Middleweight Champion, and has also formerly competed for DREAM, and Jungle Fight.
 As of February 11, 2016, he is #3 in official UFC middleweight rankings.
Matt Hume (born July 14, 1966) is an American mixed martial artist.
 He is the founder and head trainer at AMC Pankration in Kirkland, WA, which is home to UFC flyweight champion Demetrious Johnson, ONE bantamweight champion Bibiano Fernandes and he has trained numerous world class fighters including Josh Barnett, Tim Boetsch Bob Sapp, Chris Leben, Hayato Sakurai, Akira Shoji, Matt Brown, Rich Franklin, Mario Miranda and Caros Fodor.
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).
Frank Shamrock (born Frank Alisio Juarez, III; December 8, 1972) is an American former mixed martial artist.
 Shamrock was the first to hold the UFC Middleweight Championship (later renamed the UFC Light Heavyweight Championship) and retired as the four-time defending undefeated champion.
 Shamrock was the No. 1 ranked pound for pound UFC fighter in the world during his reign as the UFC Middleweight Champion.
 Shamrock has won numerous titles in other martial arts organizations, including the interim King of Pancrase title, the WEC Light Heavyweight Championship and the Strikeforce Middleweight Championship.
Christopher James "Chris" Weidman (born June 17, 1984) is an American mixed martial artist.
 He is the former UFC Middleweight Champion.
 He is currently ranked as the #6 middleweight in the world.
 In 2013, he earned worldwide prominence by becoming the first man to defeat Anderson Silva inside the UFC to become the Middleweight Champion, which he held for approximately two and a half years.
 Chris Weidman successfully defended the belt three times before losing it to Luke Rockhold.
Michael Bisping ( , ; born 28 February 1979) is an English mixed martial artist and actor.
 He fights in the Ultimate Fighting Championship (UFC), and is the current UFC Middleweight Champion.
 He is a former Cage Rage Light Heavyweight Champion, and "The Ultimate Fighter 3" Light Heavyweight Tournament winner.
 At UFC 78, he became the first English fighter in a UFC main event and at UFC 199, he became the first English fighter to win a UFC championship.
Timothy A. Boetsch ( ; born January 28, 1981) is an American professional mixed martial artist currently fighting in the Middleweight division of the Ultimate Fighting Championship.
 In addition to the UFC, Boetsch has formerly competed as an alternate for the New York Pitbulls in the International Fight League and King of the Cage.
 He holds victories over former UFC Champion Johny Hendricks and former bellator middleweight champion Hector Lombard.
 As of July 21, 2017, he is ranked #13 in official UFC Middleweight rankings.
Luke Skyler Rockhold (born October 17, 1984) is an American mixed martial artist competing in the UFC, where he is the former UFC Middleweight Champion.
 He won the title on December 12, 2015 by defeating prior champion, the undefeated Chris Weidman via 4th round TKO.
 He lost his belt in his first title defense against Michael Bisping, who stepped in after Weidman pulled out of their scheduled rematch.
 A two-time world champion, Rockhold also won the Strikeforce Middleweight Championship by defeating Ronaldo Souza on September 10, 2011 via unanimous decision.
 Rockhold defended the title twice and was the last man to hold the belt, before Strikeforce was officially taken over by the UFC.
 He is currently ranked the #2 middleweight and #12 official pound-for-pound fighter by the UFC and other publications like Fight Matrix and Sherdog.
 Luke is also an avid surfer and skateboarder.

Question: What is the UFC Middleweight ranking of one of Matt Hume's students?
Answer: #13