It is known that 1+2+3+...+49+50=1275, then 1+2+3+...+49+50+49+48+...+3+2+1=how much.
已知1+2+3+…+49+50=1275，那么1+2+3+…+49+50+49+48+…+3+2+1=多少．
<gadget id="calculator">1_275 - 50</gadget>
<output>1_225</output>

<gadget id="calculator">1_275 + 1_225</gadget>
<output>2_500</output>

<result>2_500</result>