What is the sum of all the simplest proper fractions with denominator 14?
所有分母为14的最简真分数的和是多少．
<gadget id="calculator">1 / 14</gadget>
<output>1/14 = around 0.071429</output>

<gadget id="calculator">3 / 14</gadget>
<output>3/14 = around 0.214286</output>

<gadget id="calculator">5 / 14</gadget>
<output>5/14 = around 0.357143</output>

<gadget id="calculator">9 / 14</gadget>
<output>9/14 = around 0.642857</output>

<gadget id="calculator">11 / 14</gadget>
<output>11/14 = around 0.785714</output>

<gadget id="calculator">13 / 14</gadget>
<output>13/14 = around 0.928571</output>

<gadget id="calculator">(1/14) + (3/14) + (5/14) + (9/14) + (11/14) + (13/14)</gadget>
<output>3</output>

<result>3</result>