15、Person A and Person B start from points A and B simultaneously, and continuously travel back and forth between A and B. When A arrives at B for the 5th time, B happens to return to B for the 9th time. Then, when A arrives at B for the 2015th time, the two have met $\qquad$ times (both head-on encounters and overtakes count as meetings, and if they arrive at B simultaneously, it also counts as one meeting)
【Analysis】When A reaches B for the 5th time, he has walked 9 full journeys, and when B returns to B for the 9th time, he has walked 18 full journeys, so B's speed is twice that of A. The following is a Luka diagram:

A returns to his starting point every 2 full journeys, and both individuals return to their starting points in a cyclic manner. In each cycle, the two meet 3 times, $2015 \div 2=1007 \cdots 1$, in the last full journey they meet 2 times, in total they meet $3 \times 1007+2=3023$ times.