user: You are a structured reasoning expert tasked with solving problems step by step. 
You first think about the reasoning process in the mind and then provide the answer. The reasoning process and answer should be enclosed within <think> </think> and <answer> </answer> tags, respectively, i.e., <think> reasoning process here </think> <answer> answer here </answer>. 
Given a question and the associated knowledge graph triplets (entity, relation, entity), you are asked to answer the question with these triplets and your own knowledge. 
You can break down the original question into several sub-questions and explore the given knowledge graph to solve them step-by-step. If there are multiple possible answers, choose one as the final answer. 
After thinking, when you finally reach a conclusion, clearly state the answer within <answer> </answer> tags, i.e., <answer> answer here </answer>. 
Question: Which currently working coach has coached the Baltimore Ravens? 
Knowledge Triplets: Baltimore Ravens at New England Patriots, 2010-01-10, american_football.football_game.receiving, m.09rlsdy
m.0_r0s7v, american_football.football_historical_coach_position.team, Baltimore Ravens
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.07920r8
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlck8
Indianapolis Colts at Baltimore Ravens, 2009-11-22, common.topic.notable_for, g.1256xshrj
Baltimore Ravens, sports.sports_team.league, m.0crtf92
m.062_hjj, american_football.football_historical_coach_position.coach, Rex Ryan
m.0107gkfl, american_football.football_historical_coach_position.coach, Dave Clawson
Baltimore Ravens, american_football.football_team.away_games, Baltimore Ravens at New England Patriots, 2010-01-10
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.receiving, m.07928bn
Current head coach, type.property.reverse_property, Current team head coached
John Harbaugh, people.person.profession, American Football coach
Current team head coached, rdf-schema#range, American football team
Current head coach, owl#inverseOf, Current team head coached
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.07923tk
Cincinnati Bengals at Baltimore Ravens, 2008-09-07, common.topic.notable_for, g.125bnwwyh
m.09ynvv7, common.webpage.topic, Baltimore Ravens
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.07921zh
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kngc_
m.0g9fn36, common.webpage.topic, Baltimore Ravens
m.062_hht, american_football.football_historical_coach_position.coach, Rex Ryan
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.rushing, m.08nlc9g
Kansas City Chiefs at Baltimore Ravens, 2009-09-13, common.topic.notable_for, g.1259t82yt
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.0793g0t
Detroit Lions at Baltimore Ravens, 2009-12-13, common.topic.notable_for, g.125ct5czw
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.away_team, Baltimore Ravens
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.season, 2008 NFL season
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.passing, m.09kng64
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.home_team, Cleveland Browns
m.09w9wnc, common.webpage.topic, Baltimore Ravens
Baltimore Ravens, common.topic.webpage, m.09w9wnc
Current head coach, rdf-schema#range, American football head coach
m.010q783h, american_football.football_historical_coach_position.coach, Jim O'Neil
Baltimore Ravens, common.topic.article, m.01ctj
Cleveland Browns at Baltimore Ravens, 2008-09-21, common.topic.notable_for, g.125689xb3
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.07923sq
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.passing, m.0793fwt
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, common.topic.notable_for, g.125b1mr5x
Baltimore Ravens, american_football.football_team.historical_coaching_staff, m.062_hjj
m.010q7813, american_football.football_historical_coach_position.coach, Jim O'Neil
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.07920sl
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlcc4
Baltimore Ravens, common.image.appears_in_topic_gallery, Baltimore Ravens
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.season, 2008 NFL season
Current team head coached, type.property.schema, American football head coach
Pittsburgh Steelers at Baltimore Ravens, 2009-11-29, common.topic.notable_for, g.125689xm8
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlckz
Baltimore Ravens at Green Bay Packers, 2009-12-07, common.topic.notable_for, g.1256dfr8p
Tennessee Titans at Baltimore Ravens, 2008-10-05, common.topic.notable_for, g.125bwrm90
Baltimore Ravens at New England Patriots, 2009-10-04, american_football.football_game.receiving, m.07p5x0c
Baltimore Ravens, sports.professional_sports_team.owner_s, Steve Bisciotti
Baltimore Ravens at Oakland Raiders, 2010-01-03, common.topic.notable_for, g.1258lhk8h
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.07920sy
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.07921_s
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.0793g15
John Harbaugh, people.person.profession, Coach
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlcbt
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.receiving, m.07921l7
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kng9b
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlckm
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kngf0
Baltimore Ravens, common.topic.notable_for, g.1258t61gm
Baltimore Ravens at San Diego Chargers, 2009-09-20, american_football.football_game.receiving, m.07mljfm
m.0nhrhj_, sports.sports_team_coach_tenure.coach, Jim Caldwell
Baltimore Ravens at New England Patriots, 2009-10-04, american_football.football_game.receiving, m.07p5x2w
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.0792bk2
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.07920rr
m.062_hjj, american_football.football_historical_coach_position.team, Baltimore Ravens
Current head coach, rdf-schema#domain, American football team
Baltimore Ravens, american_football.football_team.away_games, Baltimore Ravens at New York Giants, 2008-11-16
m.010rlfxx, american_football.football_historical_coach_position.coach, Joker Phillips
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlcf4
Baltimore Ravens, common.topic.webpage, m.0b45wx5
Baltimore Ravens at New York Giants, 2008-11-16, common.topic.notable_for, g.1256z3vg3
Baltimore Ravens, american_football.football_team.historical_coaching_staff, m.0_r0s7v
Baltimore Ravens at New England Patriots, 2010-01-10, american_football.football_game.passing, m.09rlsb2
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kngfc
Baltimore Ravens, sports.sports_team.coaches, m.0nhrhj_
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kng7z
Baltimore Ravens at New England Patriots, 2009-10-04, common.topic.notable_for, g.1256xshrh
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.0792bg6
m.062_hj8, american_football.football_historical_coach_position.coach, Rex Ryan
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.home_team, Pittsburgh Steelers
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.0792dym
m.011w_zjc, sports.sports_team_coach_tenure.team, Baltimore Ravens
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.07923vc
Jim O'Neil, people.person.profession, Coach
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.receiving, m.07921k6
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.season, 2009 NFL season
m.0n_xsm9, american_football.football_historical_coach_position.team, Baltimore Ravens
m.0nhrhj_, sports.sports_team_coach_tenure.team, Baltimore Ravens
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.receiving, m.07921kx
m.0b45wx5, common.webpage.topic, Baltimore Ravens
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.home_team, Cleveland Browns
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kng8_
Current head coach, type.property.expected_type, American football head coach
Baltimore Ravens, american_football.football_team.historical_coaching_staff, m.062_hj8
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.home_team, Pittsburgh Steelers
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.rushing, m.08nlc8m
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.0792bfk
Current team head coached, type.property.expected_type, American football team
Baltimore Ravens at Minnesota Vikings, 2009-10-18, common.topic.notable_for, g.125524x61
Baltimore Ravens at New England Patriots, 2009-10-04, american_football.football_game.receiving, m.07p5wxt
Baltimore Ravens at New England Patriots, 2009-10-04, american_football.football_game.passing, m.07p5wsk
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kngdp
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.passing, m.08nlcgv
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.receiving, m.079288k
Baltimore Ravens at Indianapolis Colts, 2008-10-12, common.topic.notable_for, g.125dtpqpk
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.passing, m.079286c
Baltimore Ravens at New England Patriots, 2009-10-04, american_football.football_game.receiving, m.07p5wy5
Baltimore Ravens, american_football.football_team.division, AFC North
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.0792bjl
Baltimore Ravens at Indianapolis Colts, 2010-01-16, common.topic.notable_for, g.1255525gq
Baltimore Ravens at New England Patriots, 2009-10-04, american_football.football_game.receiving, m.07p5wxg
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.07921_4
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlcdp
Baltimore Ravens at San Diego Chargers, 2009-09-20, american_football.football_game.receiving, m.07mljhk
Baltimore Ravens at Miami Dolphins, 2009-01-04, common.topic.notable_for, g.1258jnnkc
New York Jets, american_football.football_team.current_head_coach, Rex Ryan
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.passing, m.0792b9p
Baltimore Ravens at Dallas Cowboys, 2008-12-20, common.topic.notable_for, g.1255cshr8
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.07920s5
John Harbaugh, american_football.football_coach.current_team_head_coached, Baltimore Ravens
Baltimore Ravens at New England Patriots, 2010-01-10, american_football.football_game.passing, m.09rls5w
Baltimore Ravens, american_football.football_team.away_games, Baltimore Ravens at Pittsburgh Steelers, 2009-01-18
Cleveland Browns at Baltimore Ravens, 2009-09-27, common.topic.notable_for, g.1258jnnv9
Baltimore Ravens, american_football.football_team.historical_coaching_staff, m.062_hj0
m.04229n6, common.webpage.topic, Baltimore Ravens
m.0115jprj, sports.sports_team_coach_tenure.coach, Matt McCoy
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlcd6
Baltimore Ravens, common.topic.notable_types, American football team
Baltimore Ravens at Tennessee Titans, 2009-01-10, common.topic.notable_for, g.1257dslcn
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kng9p
Baltimore Ravens, common.topic.webpage, m.0g9fn36
Baltimore Ravens, common.topic.webpage, m.09ynvv7
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlcjy
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.receiving, m.079289p
Current team head coached, rdf-schema#domain, American football head coach
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.0793fz1
Baltimore Ravens at New England Patriots, 2010-01-10, common.topic.notable_for, g.1254zjjl3
American football team, type.type.properties, Current head coach
m.010rlvgq, american_football.football_historical_coach_position.coach, Chris Leak
m.062_hj0, american_football.football_historical_coach_position.team, Baltimore Ravens
Baltimore Ravens, sports.sports_team.sport, American football
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.away_team, Baltimore Ravens
Pittsburgh Steelers at Baltimore Ravens, 2008-12-14, common.topic.notable_for, g.1256knc1q
Current head coach, type.property.schema, American football team
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, common.topic.notable_for, g.12554g3x2
Detroit Lions, american_football.football_team.current_head_coach, Jim Caldwell
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.0792dxl
Steve Bisciotti, sports.sports_team_owner.teams_owned, Baltimore Ravens
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.passing, m.0792dtd
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.0792dwk
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.season, 2008 NFL season
Baltimore Ravens at New England Patriots, 2010-01-10, american_football.football_game.receiving, m.09rlsdl
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.0793g09
Baltimore Ravens, american_football.football_team.current_head_coach, John Harbaugh
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.0792dxy
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.07921yz
Dave Clawson, people.person.profession, American Football coach
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.passing, m.08nlc80
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.receiving, m.0792898
Baltimore Ravens at New England Patriots, 2010-01-10, american_football.football_game.receiving, m.09rls9r
Baltimore Ravens at Houston Texans, 2008-11-09, common.topic.notable_for, g.1255sgcxy
Baltimore Ravens, sports.sports_team.league, m.0crt4nx
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.away_team, Baltimore Ravens
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.079220n
Baltimore Ravens, sports.sports_team.coaches, m.011w_zjc
Baltimore Ravens, american_football.football_team.conference, American Football Conference
Philadelphia Eagles at Baltimore Ravens, 2008-11-23, common.topic.notable_for, g.1256dr5m7
Baltimore Ravens at San Diego Chargers, 2009-09-20, american_football.football_game.receiving, m.07mljgg
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.home_team, New York Giants
Baltimore Ravens at Cleveland Browns, 2008-11-02, common.topic.notable_for, g.1254zbtnw
Baltimore Ravens at New England Patriots, 2010-01-10, american_football.football_game.receiving, m.09rls9d
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.0793f_3
m.062_hj8, american_football.football_historical_coach_position.team, Baltimore Ravens
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlccv
Baltimore Ravens at New England Patriots, 2009-10-04, american_football.football_game.receiving, m.07p5wws
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.0793fzj
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.0792dy8
Rex Ryan, american_football.football_coach.current_team_head_coached, New York Jets
Baltimore Ravens at New England Patriots, 2010-01-10, american_football.football_game.receiving, m.09rlscx
Nick Bollettieri, people.person.profession, Coach
Baltimore Ravens at New England Patriots, 2009-10-04, american_football.football_game.away_team, Baltimore Ravens
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.away_team, Baltimore Ravens
Baltimore Ravens at San Diego Chargers, 2009-09-20, common.topic.notable_for, g.125cbz_15
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.receiving, m.079288x
m.011w_zjc, sports.sports_team_coach_tenure.coach, Randy Brown
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.07923vw
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.home_team, Pittsburgh Steelers
Baltimore Ravens, american_football.football_team.historical_coaching_staff, m.0n_xsm9
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.passing, m.07921gw
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.0792dw6
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.passing, m.07923p2
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.receiving, m.0792207
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.0792bh4
Baltimore Ravens at San Diego Chargers, 2009-09-20, american_football.football_game.passing, m.07mljkv
Washington Redskins at Baltimore Ravens, 2008-12-07, common.topic.notable_for, g.1257jmky0
Baltimore Ravens at New England Patriots, 2009-10-04, american_football.football_game.receiving, m.07p5x1c
Jack Harbaugh, people.person.profession, Coach
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kng89
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, common.topic.notable_for, g.1259v06hm
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.rushing, m.08nlchg
Baltimore Ravens, common.topic.image, Baltimore Ravens
Jim Caldwell, people.person.profession, Coach
Current team head coached, type.property.master_property, Current head coach
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.passing, m.09kngbj
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.0792dwx
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kng8n
Baltimore Ravens at New England Patriots, 2009-10-04, american_football.football_game.receiving, m.07p5wwf
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.away_team, Baltimore Ravens
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.07923w8
Baltimore Ravens at New England Patriots, 2010-01-10, american_football.football_game.receiving, m.09rls8c
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.0792bj6
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kngdb
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.receiving, m.07928b1
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.receiving, m.0792bhs
m.0_r0s7v, american_football.football_historical_coach_position.coach, Ted Marchibroda
Baltimore Ravens at Cleveland Browns, 2009-11-16, common.topic.notable_for, g.1256g41m0
Jim Caldwell, sports.sports_team_coach.teams_coached, m.0nhrhj_
Baltimore Ravens, common.topic.webpage, m.04229n6
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.receiving, m.0792dx7
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.season, 2009 NFL season
Baltimore Ravens, american_football.football_team.current_head_coach, John Harbaugh
Baltimore Ravens, sports.sports_team.league, m.0crt9hl
Coach, people.person.profession, John Harbaugh
Baltimore Ravens at New York Giants, 2008-11-16, american_football.football_game.passing, m.07921v3
m.062_hj0, american_football.football_historical_coach_position.coach, Rex Ryan
Baltimore Ravens, american_football.football_team.historical_coaching_staff, m.062_hht
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlcch
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.receiving, m.08nlcfp
Jim Caldwell, american_football.football_coach.current_team_head_coached, Detroit Lions
Baltimore Ravens at Pittsburgh Steelers, 2009-01-18, american_football.football_game.season, 2008 NFL season
Baltimore Ravens at Cleveland Browns, 2008-11-02, american_football.football_game.receiving, m.07921kk
Baltimore Ravens at Cleveland Browns, 2009-11-16, american_football.football_game.passing, m.08nlcg3
Baltimore Ravens at Pittsburgh Steelers, 2008-09-29, american_football.football_game.passing, m.07920nz
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.receiving, m.09kngfq
Baltimore Ravens at Pittsburgh Steelers, 2009-12-27, american_football.football_game.away_team, Baltimore Ravens
m.062_hht, american_football.football_historical_coach_position.team, Baltimore Ravens

Answer: John Harbaugh