Instruction: Parse the product information to locate the target attribute, and then provide the extracted value of the target attribute and its source in the output, specifying None if the attribute is not present.

Input:
Product title: 2.4GHz Wireless Optical Nano Mouse (Red) (USB)
Product description: Optical 2.4 GHz Wireless Nano Mouse Model: MP2275RED. Features: Optical Sensing Technology, 2.4 GHz Wireless Connectivity, Automatic Wireless Synchronization, Scalable DPI, Built-in Scroll Wheel and Stowable Nano Receiver. Package Contents: Optical 2.4 GHz Wireless Nano Mouse, Nano Receiver 2 AAA Batteries, User's Manual and Warranty Information. System Requirements: PC and Mac Compatibles, Windows 2000, XP, Vista, and 7, Mac OS 10.3 and above. An Available USB Port
Product feature: Optical Sensing Technology, 2.4 GHz Wireless Connectivity, Automatic Wireless Synchronization, Built-in Scroll Wheel, Stowable Nano Receiver
Product brand: Gear Head
Target attributes: Number of Buttons
Answer: attribute: number of buttons
value: None
source: None