How many simple fractions have the denominator 135?
分母是135的最简真分数共有多少个．
<gadget id="calculator">27 - 9</gadget>
<output>18</output>

<gadget id="calculator">45 + 18</gadget>
<output>63</output>

<gadget id="calculator">135 - 63</gadget>
<output>72</output>

<result>72</result>