Subtract 5 from 3 times of a certain number to calculate the answer, then subtract 5 from the answer after 3 times to calculate the answer, repeat this way 4 times, the final calculation result is 691, what is the original number?
将某数的3倍减5，计算出答案，将答案再3倍后减5，计算出答案，这样反复经过4次，最后计算的结果为691，那么原数是多少．
<gadget id="calculator">691 + 5</gadget>
<output>696</output>

<gadget id="calculator">696 / 3</gadget>
<output>232</output>

<gadget id="calculator">232 + 5</gadget>
<output>237</output>

<gadget id="calculator">237 / 3</gadget>
<output>79</output>

<gadget id="calculator">79 + 5</gadget>
<output>84</output>

<gadget id="calculator">84 / 3</gadget>
<output>28</output>

<gadget id="calculator">28 + 5</gadget>
<output>33</output>

<gadget id="calculator">33 / 3</gadget>
<output>11</output>

<result>11</result>