Instruction: Extract the value of the target attribute from the given product information and output it along with the corresponding source.

Input:
Product title: Mixed Colors Agate Coaster Set of Four Gift Boxed
Product description: Set of 4 agate coasters. Using natural products are all the rage. These look terrific at the bar, pool side, or elegant table setting. Rubber bumpers on bottom to protect furniture--non-absorbant. The photo is only a sample of the coaster colors you may be getting. Agates come in varing shades of Purple, blue, teal, pink, black, red, brown.
Product feature: 4-5 inch average size agate, Polished, gift boxed, protective bumpers on bottom
Product brand: Something Glassy
Target attributes: Quantity
Answer: attribute: quantity
value: of four
source: product title
attribute: quantity
value: 4 agate coasters
source: product description
attribute: quantity
value: four
source: product title