How many creases can be obtained by folding a rectangular strip of paper in half 6 times?
把长方形的纸条对折6次可得多少条折痕．
<gadget id="calculator">2 ** 6</gadget>
<output>64</output>

<gadget id="calculator">64 - 1</gadget>
<output>63</output>

<result>63</result>