## Task 1 - 320521

A sales representative residing in Dresden (D) wants to visit each of the cities Erfurt (E), Magdeburg (M), Potsdam (P), and Schwerin (S) exactly once and then return to their residence.

The first city to be visited on this trip should be Erfurt, and the order of the other cities is not yet determined. The illustration shows a possible route.

![](https://cdn.mathpix.com/cropped/2024_06_06_b85a894aa8dbf722a7b3g-0137.jpg?height=285&width=255&top_left_y=383&top_left_x=1483)

List all possible travel routes that can be chosen under the given conditions! How many travel routes are there in total? A justification is not required.
The choice can be made from exactly the following travel routes:

$$
\begin{array}{lll}
D-E-M-P-S-D, & D-E-M-S-P-D, & D-E-P-M-S-D \\
D-E-P-S-M-D, & D-E-S-M-P-D, & D-E-S-P-M-D
\end{array}
$$

These are a total of 6 travel routes. The specification of the routes can be done in this or a similar abbreviation or graphically.