10. There are 8 red, 8 white, and 8 yellow chopsticks. Without looking, how many chopsticks must be taken out to ensure that at least two pairs of chopsticks are of different colors? $\qquad$
10. 11.

Since among 11 chopsticks there must be a pair of the same color (let's say yellow), the number of black or white chopsticks must be at least 3, among which there must be a pair of the same color, i.e., both black or both white. Therefore, 11 chopsticks ensure success. However, if only 10 chopsticks are taken, it is possible to have 8 yellow, 1 black, and 1 white, which does not meet the requirement.