Calculation: 1*2*3*4*5*6*7-(1+2*1*2+3*1*2*3+…+6*1*2*3*4*5*6)= How many.
计算：1*2*3*4*5*6*7-(1+2*1*2+3*1*2*3+…+6*1*2*3*4*5*6)=多少．
<gadget id="calculator">1 * 2</gadget>
<output>2</output>

<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<result>1</result>