In 100-999, how many exactly have the same two digits.
在100-999中，恰好有两位数字相同的共有多少个．
<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<gadget id="calculator">9 * 9 * 2</gadget>
<output>162</output>

<gadget id="calculator">81 + 162</gadget>
<output>243</output>

<result>243</result>