7440
Later in the episode , two alien conspirators acknowledge , in private conversation , that the Sandkings could become a serious problem in about thirty years , assuming that they could survive in a methane-based atmosphere , which the aliens intended to gradually transform from the Earth 's human-friendly one .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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