I need to write a letter to my friend about a recent vacation. The letter should be informal and friendly. Can you help me draft it? The response should contain at least 3 paragraphs separated with markdown dividers. Include keywords such as "vacation," "fun," "relax," and "memories." At the end of your response, please explicitly add a postscript starting with "P.S."
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P.S.
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P.S.

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