Nanjing borders Yangzhou to the northeast, one town downstream when following the north bank of the Yangtze, Zhenjiang to the east, one town downstream when following the south bank of the Yangtze, and Changzhou to the southeast. On its western boundary is Anhui province, where Nanjing borders <answer>five</answer> prefecture-level cities, Chuzhou to the northwest, Wuhu, Chaohu and Maanshan to the west and Xuancheng to the southwest.
How many prefecture-size cities are in the province of Anhui?
five