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 is the legal case regarding; residential segregation? 
Knowledge Triplets: Swann v. Charlotte-Mecklenburg Board of Education, law.legal_case.subject, Residential segregation
Residential segregation, law.legal_case.subject, Swann v. Charlotte-Mecklenburg Board of Education
Swann v. Charlotte-Mecklenburg Board of Education, law.legal_case.court, Supreme Court of the United States
m.0cytgl, dataworld.gardening_hint.replaced_by, Swann v. Charlotte-Mecklenburg Board of Education
Desegregation busing, law.legal_subject.legal_cases, Swann v. Charlotte-Mecklenburg Board of Education
m.0r2lvrr, dataworld.gardening_hint.last_referenced_by, Swann v. Charlotte-Mecklenburg Board of Education
Swann v. Charlotte-Mecklenburg Board of Education, user.avh.default_domain.ellerdale_topic.ellerdale_id, 0081-0602
Swann v. Charlotte-Mecklenburg Board of Education, law.legal_case.subject, Desegregation busing
Residential segregation, law.legal_subject.legal_cases, Swann v. Charlotte-Mecklenburg Board of Education
Swann v. Charlotte-Mecklenburg Board of Education, time.event.end_date, 1971
Swann v. Charlotte-Mecklenburg Board of Education, law.legal_case.subject, Racial segregation
Racial segregation, law.legal_subject.legal_cases, Swann v. Charlotte-Mecklenburg Board of Education
Swann v. Charlotte-Mecklenburg Board of Education, time.event.start_date, 1970
Supreme Court of the United States, law.court.legal_cases, Swann v. Charlotte-Mecklenburg Board of Education

Answer: Swann v. Charlotte-Mecklenburg Board of Education