Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Your letters will thank you!

Every letter I have mailed with a Columbian envelope has arrived safe and sound at its destination. There is no brand of envelope I would recommend more highly. Each of these envelopes provides without fail an unambiguous separation between the space inside, where your letter is, and the space outside, where can be found many things that might be dangerous to your letter.