CREATE TABLE table_17566 ("Stage" TEXT, "Winner" TEXT, "General classification" TEXT, "Points classification" TEXT, "Mountains classification" TEXT, "Young rider classification" TEXT, "Trofeo Fast Team" TEXT)

Name the general classification of stage 15
SELECT COUNT("General classification") FROM table_17566 WHERE "Stage" = '15'
SELECT COUNT("General classification") FROM "table_17566" WHERE "Stage" = '15'