I want to know the answer to the following question:
In what year were Bois de Boulogne and Bois de Vincennes annexed?
All the background I'm provided with is that "Excluding the outlying parks of Bois de Boulogne and Bois de Vincennes, Paris covers an oval measuring about 87 km2 (34 sq mi) in area, enclosed by the 35 km (22 mi) ring road, the Boulevard Périphérique.". Is that enough to answer the question?