Instruct: Classify an Amazon review as either positive or negative.
Query: tennis shoes

After playing in these for about 2 weeks. Thumbs up. At the start, they were very stiff and gave me blisters on my heal. I begain to wonder if these were the shoes for me. Happily now, thery are very comfortable. And Even here in the Las Vegas summer heat, my feet remain the least of my heat worries.I am happy!