What is a four-letter word for "energy conservation"?

Saving clothes and food, long sections in the festival, changing the festival to make it easier to practice, branching out horizontally, intertwined, a limb and a section, shrinking clothes and food, a limb and a half a section, losing one's body and losing one's section, other branches, sharpening the wind and the festival, flourishing branches and details, not sticking to small details, loyalty, filial piety, righteousness, branching out of the festival, practicing frugality and thriftiness, the side branching and the end of the festival, increasing revenue and saving money, going in and out of the city, opening up the sources of energy and saving the flow of funds, not sticking to small details, branching out of the festival, saving clothes and saving money, clear and bright and bright and clear and clear and bright and bright and clear and bright and clear and bright and clear and bright and clear and bright and clear and clear, High style and high integrity, practicing frugality, minor details, the late festival is not guaranteed, when the flowers fall, the branch is divided into sections, do not repair the small sections, the big sections are not taken

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