In a pile of logs, there are 10 logs in the top layer and 19 logs in the bottom layer. The bottom layer is always one more than the top layer. How many logs are there in total?
一堆圆木，最上面一层有10根，最下面一层有19根，下面一层总比上面一层多一根，这堆圆木共有多少根．
<gadget id="calculator">10 + 19</gadget>
<output>29</output>

<gadget id="calculator">19 - 10</gadget>
<output>9</output>

<gadget id="calculator">9 + 1</gadget>
<output>10</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">29 * 5</gadget>
<output>145</output>

<result>145</result>