The less than side is gonna be a less than sign, and then the word and is going to become not one & but two ampersands back to back, and we'll see why it's two and not one before long.

小于“侧还是用的“小于“,而中间的“and“将去掉,换成两个紧挨着的&符号，但至于为什么是&&而不是,我们以后会提到。

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