Make sure that at least two chopsticks are the same. In the worst case, you will be red, white and black for the first three times. If you touch them for the fourth time, there must be two chopsticks of the same color.

Take at least 6 pairs of chopsticks and ensure that there are 2 pairs of chopsticks with the same color.

For example, one is red, one is white and the other is black. If you take another pair, if it is not red, it will be another pair, but if it is red, you can't make it up, so you must take one, and you can make a second pair no matter what color.