What are the key features of a modern smartphone? Your response should contain at least 6 sentences. The response must have 3 sections. Mark the beginning of each section with Section 1, Section 2, and Section 3. In your response, the word "smartphone" should appear at least 4 times. Include the keywords: camera, battery, and processor. At the end of your response, please explicitly add a postscript starting with P.S.
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