ribbon made of beads strung together in the order of red, blue, red, blue... with red beads at the head and tail. If 28 blue beads are used to string one such ribbon, how many red beads are needed to string two such ribbons?
一条用珠子按红、蓝、红、蓝…顺序串成的彩带，头尾都是红珠子．如果串一条这样的彩带用了28颗蓝珠子，那么串两条这样的彩带需要多少颗红珠子？
<gadget id="calculator">28 / 1</gadget>
<output>28</output>

<gadget id="calculator">28 + 1</gadget>
<output>29</output>

<gadget id="calculator">29 * 2</gadget>
<output>58</output>

<result>58</result>