How many authors finished the paper "An Improved Active Suspension Model for Attitude Control of Electric Vehicles" together?
authors refers to AuthorId; 'An Improved Active Suspension Model for Attitude Control of Electric Vehicles' is the Title of a paper; A paper can have more than one author. Co-authorship can be derived from (paper ID, author ID) pair.
SELECT COUNT(T2.AuthorId) FROM Paper AS T1 INNER JOIN PaperAuthor AS T2 ON T1.Id = T2.PaperId WHERE T1.Title = 'An Improved Active Suspension Model for Attitude Control of Electric Vehicles'
database name:db_id authors
Author table Author Cols: Id dtype integer, Name dtype text, Affiliation dtype text, 
Conference table Conference Cols: Id dtype integer, ShortName dtype text, FullName dtype text, HomePage dtype text, 
Journal table Journal Cols: Id dtype integer, ShortName dtype text, FullName dtype text, HomePage dtype text, 
Paper table Paper Cols: Id dtype integer, Title dtype text, Year dtype integer, ConferenceId dtype integer, JournalId dtype integer, Keyword dtype text, 
PaperAuthor table PaperAuthor Cols: PaperId dtype integer, AuthorId dtype integer, Name dtype text, Affiliation dtype text, 
