There is a string of numbers (1/1), (1/2), (2/2), (1/2), (1/3), (2/3), (3/3), (2/3) , (1/3), (1/4), (2/4), (3/4), (4/4), (3/4), (2/4), (1/4), ... What is the fraction of this series of numbers counting from the left that is (10/10).
有一串数(1/1)、(1/2)、(2/2)、(1/2)、(1/3)、(2/3)、(3/3)、(2/3)、(1/3)、(1/4)、(2/4)、(3/4)、(4/4)、(3/4)、(2/4)、(1/4)、…这一串数从左开始数第多少个分数是(10/10)．
<gadget id="calculator">81 + 10</gadget>
<output>91</output>

<result>91</result>