Red Boy uses "Samadhi Real Fire", and sees red flames and big fires igniting the sky. Wukong can't win for a while, so he meets the Dragon King of the Four Seas to borrow rainwater. The average hourly rainfall of the four is 370 millimeters, and the average hourly rainfall of the Dragon King of the East China Sea is 300 millimeters. The Dragon King of the West Sea is 350 millimeters, and the Dragon King of the South China Sea is 400 millimeters. Ask the Dragon King of the North Sea how many millimeters of rainfall?
红孩儿使出「三昧真火」，只见红焰焰、大火烧空，悟空一时不能得胜，于是面见四海龙王商借雨水，四人平均时雨量为370毫米，东海龙王时雨量300毫米，西海龙王350毫米，南海龙王400毫米，问北海龙王时雨量几毫米？
<gadget id="calculator">370 * 4</gadget>
<output>1_480</output>

<gadget id="calculator">300 + 350 + 400</gadget>
<output>1_050</output>

<gadget id="calculator">1_480 - 1_050</gadget>
<output>430</output>

<result>430</result>