SCHEMA:
CREATE TABLE debate_people (Negative VARCHAR); CREATE TABLE people (Name VARCHAR, People_ID VARCHAR)
USER:
Show the names of people who have been on the negative side of debates at least twice.

QUERY:
SELECT T2.Name FROM debate_people AS T1 JOIN people AS T2 ON T1.Negative = T2.People_ID GROUP BY T2.Name HAVING COUNT(*) >= 2