The Olympic standard swimming pool is 50 meters long, 30 meters wide, and 2.5 meters deep. The bottom and surrounding areas of the swimming pool should be covered with a waterproof coating. At least how many square meters of waterproof coating should be prepared?
奥运会标准游泳池长50米、宽30米、深2.5米，要在游泳池的底部和四周覆盖防水涂层．至少要准备多少平方米的防水涂层？
<gadget id="calculator">50 * 2.5</gadget>
<output>125</output>

<gadget id="calculator">30 * 2.5</gadget>
<output>75</output>

<gadget id="calculator">125 + 75</gadget>
<output>200</output>

<gadget id="calculator">200 * 2</gadget>
<output>400</output>

<gadget id="calculator">50 * 30</gadget>
<output>1_500</output>

<gadget id="calculator">400 + 1_500</gadget>
<output>1_900</output>

<result>1_900</result>