Among the coaches who taught the teams in 1922's Stanley Cup finals, how many of them are from the USA?
from the USA refers to birthCountry = 'USA'; year = 1922;
SELECT COUNT(DISTINCT T3.coachID) FROM Coaches AS T1 INNER JOIN TeamsSC AS T2 ON T1.year = T2.year AND T1.tmID = T2.tmID INNER JOIN Master AS T3 ON T1.coachID = T3.coachID WHERE T2.year = 1922 AND T3.birthCountry = 'USA'