Among the players who played 72 games, how many are left-shooters?
played 72 games refers to GP = 72; left-shooters refers to shoots = 'L';
SELECT COUNT(T2.ELITEID) FROM SeasonStatus AS T1 INNER JOIN PlayerInfo AS T2 ON T1.ELITEID = T2.ELITEID WHERE T1.GP = 72 AND T2.shoots = 'L'