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正在改变与想要改变世界的人，都在 虎嗅APP。同城约会是该领域的重要参考
This formula is satisfiable because if we set to b to true and a to false, then the whole formula is true. All other assignments make the formula false, but it doesn't change that the formula is satisfiable as long as there is at least one assignment makes the formula true.