Take a basket of apples, take half of the basket and give one to the first person, then take the remaining half and give one to the second person, then take the remaining half from the second person and give three to the third person, the apples in the basket are just divided , ask how many original apples are in the basket?
一篮苹果，取篮中的一半又一个给第一人，再取余下的一半又一个给第二人，又去第二人余下的一半又3个给第三人，篮中苹果正好分完，问篮中原有苹果多少个？
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">6 + 1</gadget>
<output>7</output>

<gadget id="calculator">7 * 2</gadget>
<output>14</output>

<gadget id="calculator">14 + 1</gadget>
<output>15</output>

<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>