Not all of them, half of them. Flyby1206 had it right. JetBlue gets 12 Slot Pairs (24 Slots)

Southwest wins bid for 27 more flights at DCA airport

"It appears that there remain 5 slot pairs unaccounted from the 52 DCA slot pairs being divested by American and US Airways. Of those 52, Southwest now has 27 and JetBlue 20 (the 12 it announced this morning plus 8 it had already been leasing from AA and gets to keep on a permanent basis, per the DOJ settlement)."