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: what ship designer designed a ship that is designed by joshua humphreys? 
Knowledge Triplets: USS Congress, boats.ship.keel_laid, 1795
USS President, boats.ship.launched, 1800-04
USS Constitution, boats.ship.hull_material, Wood
USS Chesapeake, boats.ship.keel_laid, 1795-12
USS United States, boats.ship.launched, 1797-05-10
Joshua Humphreys, people.person.profession, Engineer
USS Congress, boats.ship.designer, Joshua Humphreys
Joshua Humphreys, boats.ship_designer.boats_designed, USS United States
USS Constitution, boats.ship.beam, 13.3
Avondale Shipyard, boats.ship_builder.ships_built, USNS Joshua Humphreys (T-AO-188)
Joshua Humphreys, book.book_subject.works, Joshua Humphrey's His Life And Times
USS Humphreys, boats.ship.launched, 1919-07-28
USS Constitution, boats.ship.ship_builder, Edmund Hartt
USS Chesapeake, boats.ship.beam, 12.6
Engineer, people.profession.people_with_this_profession, Joshua Humphreys
USS President, boats.ship.owners, m.0gx948h
William Doughty, boats.ship_designer.boats_designed, USS President
Joshua Humphreys, people.deceased_person.place_of_burial, Philadelphia
William Doughty, boats.ship_designer.boats_designed, USS United States
m.05kcw5j, boats.ship_ownership.ship, USS Constitution
Joshua Humphreys, symbols.name_source.namesakes, USS Humphreys
Josiah Fox, boats.ship_designer.boats_designed, USS Chesapeake
USS Chesapeake, base.aubreymaturin.ship.mentions, m.05ndb54
USS Constellation, boats.ship.launched, 1797-09-07
USS Constitution, boats.ship.draught, 6.4
New York Shipbuilding Corporation, boats.ship_builder.ships_built, USS Humphreys
USS United States, boats.ship.designer, William Doughty
USS President, boats.ship.displacement, 0.7149
USS President, boats.ship.hull_material, Wood
Pont Reading, base.usnris.nris_listing.significant_person, Joshua Humphreys
Joshua Humphreys, people.person.place_of_birth, Haverford
USS President, boats.ship.designer, William Doughty
William Doughty, boats.ship_designer.boats_designed, USS Constitution
USS Constitution, boats.ship.launched, 1797-10-10
m.05ndb54, base.aubreymaturin.ship_mention.ship, USS Chesapeake
Joshua Humphreys, boats.ship_designer.boats_designed, USS Chesapeake
Joshua Humphreys, boats.ship_designer.boats_designed, USS Constellation
USS President, boats.ship.designer, Joshua Humphreys
USS Columbus, boats.ship.place_built, Philadelphia
USS Humphreys, boats.ship.keel_laid, 1918-07-31
Joshua Humphreys, people.person.profession, Architect
Architect, people.profession.people_with_this_profession, Joshua Humphreys
USS Constitution, boats.ship.designer, Joshua Humphreys
USS Humphreys, boats.ship.ship_builder, New York Shipbuilding Corporation
Philadelphia, people.place_of_interment.interred_here, Joshua Humphreys
Joshua Humphreys, boats.ship_designer.boats_designed, USS President
USNS Joshua Humphreys (T-AO-188), boats.ship.ship_builder, Avondale Shipyard
USS Constitution, user.jamie.default_domain.boat.ship_builder, Edmund Hartt
Joshua Humphreys, people.person.date_of_birth, 1751-06-17
Edmund Hartt, boats.ship_builder.ships_built, USS Constitution
USS United States, boats.ship.designer, Joshua Humphreys
USS Constitution, boats.ship.place_built, Boston Navy Yard
m.0gx948h, boats.ship_ownership.ship, USS President
USNS Joshua Humphreys (T-AO-188), symbols.namesake.named_after, Joshua Humphreys
USS President, boats.ship.keel_laid, 1798
Joshua Humphreys, boats.ship_designer.boats_designed, USS Congress
USS United States, boats.ship_designer.boats_designed, William Doughty
USS Chesapeake, boats.ship.designer, Joshua Humphreys
Clemson-class destroyer, boats.ship_class.ships_in_class, USS Humphreys
m.05ndb4q, base.aubreymaturin.ship_mention.ship, USS Constitution
USS Constitution, boats.ship.owners, m.05kcw5j
USNS Joshua Humphreys (T-AO-188), boats.ship.launched, 1986-02-22
Haverford, location.location.people_born_here, Joshua Humphreys
Joshua Humphreys, people.person.children, Samuel Humphreys
USS Chesapeake, boats.ship.designer, Josiah Fox
USS President, boats.ship.place_built, New York City
Sailing Frigate, base.sails.sailboat.ships, USS Constitution
USS Constitution, base.aubreymaturin.ship.mentions, m.05ndb4q
Joshua Humphreys, people.person.gender, Male
USS Chesapeake, boats.ship.ship_builder, Josiah Fox
USS Constitution, boats.ship.designer, William Doughty
USS Itasca, boats.ship.place_built, Philadelphia
Joshua Humphreys, symbols.name_source.namesakes, USNS Joshua Humphreys (T-AO-188)
Samuel Humphreys, people.person.parents, Joshua Humphreys
Joshua Humphreys, boats.ship_designer.boats_designed, USS Constitution
USS Congress, boats.ship.launched, 1799-08-15
USS Humphreys, symbols.namesake.named_after, Joshua Humphreys
Joshua Humphreys, people.deceased_person.date_of_death, 1838-01-12
USS Humphreys, boats.ship.ship_class, Clemson-class destroyer
USS Constitution, boats.ship.keel_laid, 1795
USS Chesapeake, boats.ship.launched, 1799-12-02
USNS Joshua Humphreys (T-AO-188), boats.ship.keel_laid, 1984-12-17
USS Constellation, boats.ship.designer, Joshua Humphreys
USS Constitution, user.jamie.default_domain.boat.designer, Joshua Humphreys
Josiah Fox, boats.ship_builder.ships_built, USS Chesapeake
Joshua Humphrey's His Life And Times, book.written_work.subjects, Joshua Humphreys

Answer: William Doughty
Josiah Fox