Cities A and B are in different time zones. A is located \(3000 \ \text{km}\) east of B. The table below describes the schedule of an airline operating non-stop flights between A and B. All the times indicated are local and on the same day.
| Departure City | Time | Arrival City | Time |
|---|---|---|---|
| B | 8:00 am | A | 4:00 pm |
| A | 3:00 pm | B | 8:00 pm |
Assume that planes cruise at the same speed in both directions. However, the effective speed is influenced by a steady wind blowing from east to west at \(50 \ \text{km/h}\).
For any natural number $k$, let $a_k = 3^k$. The smallest natural number $m$ for which \[ (a_1)^1 \times (a_2)^2 \times \dots \times (a_{20})^{20} \;<\; a_{21} \times a_{22} \times \dots \times a_{20+m} \] is: