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

Input:
Product title: Adorable Sock Monkey Home Decor Items Throw Pillow Cover Polyester Pillowcase Cushion Cover 18 x 18 Inches
Product description: Made from soft and comfortable satin materials.these soft pillows look great with your designs, The perfect complement to your couch, pillows Case will make you the envy of the neighborhood.
Product feature: Made of durable and soft Satin Fabric. The cover is Smooth., Size: 18 x 18 Inches(1 inch error range is allowed), print on one side, the other side is white blank., It's a zippered pillow case, with a zippered opening on the side., Please Note: Just one pillow cover, not include insert., There are slight difference between the picture and the real item caused by light brightness.
Product price: $3.28
Product brand: UOOPOO
Target attributes: Size
Answer: attribute: size
value: 18 x 18
source: product title
attribute: size
value: 18 x 18
source: product feature