It is stipulated that the operation "*" is a*b=a+2b-2, then (8*7)*(4*5)=how much.
规定运算"*"为a*b=a+2b-2，则(8*7)*(4*5)=多少．
<gadget id="calculator">2 * 12</gadget>
<output>24</output>

<gadget id="calculator">24 - 2</gadget>
<output>22</output>

<gadget id="calculator">20 + 22</gadget>
<output>42</output>

<result>42</result>