Put 3 red chopsticks, 9 yellow chopsticks, 18 green chopsticks, 2 white chopsticks and 1 black chopsticks in a cloth bag, at least how many chopsticks can be touched to ensure that there are two pairs of chopsticks of the same color.
将3支红筷子，9支黄筷子，18支绿筷子，2支白筷子和1支黑筷子放在一个布袋里，至少摸多少支才能保证有两双颜色相同的筷子．
<gadget id="calculator">5 + 1 + 2 + 5</gadget>
<output>13</output>

<result>13</result>