How many times in total did the team Boston Red Stockings participate in postseason games?
select count(*) from ( select * from postseason as t1 join team as t2 on t1.team_id_winner = t2.team_id_br where t2.name = 'Boston red Stockings' union select * from postseason as t1 join team as t2 on t1.team_id_loser = t2.team_id_br where t2.name = 'Boston red Stockings' );