Question: How many players, who were drafted by Anaheim Ducks in 2008, have played for U.S. National U18 Team?
SQL: SELECT COUNT(DISTINCT T1.ELITEID) FROM PlayerInfo AS T1 INNER JOIN SeasonStatus AS T2 ON T1.ELITEID = T2.ELITEID WHERE T1.overallby = 'Anaheim Ducks' AND T1.draftyear = 2008 AND T2.TEAM = 'U.S. National U18 Team'