CREATE TABLE table_40407 ("Platform" FLOAT, "Frequency  ( per hour ) " FLOAT, "Destination" TEXT, "Service Pattern" TEXT, "Operator" TEXT, "Line" TEXT)

How many frequencies have a line of East London and destination of Crystal Palace?
SELECT COUNT("Frequency (per hour)") FROM table_40407 WHERE "Line" = 'east london' AND "Destination" = 'crystal palace'
SELECT COUNT("Frequency (per hour)") FROM "table_40407" WHERE "Destination" = 'crystal palace' AND "Line" = 'east london'