The Semantics of "_ and _" and "from _ to _" in travel planning

Hi,

Thanks for sharing the dataset and code. I have a quick question about "city A and city B" direct flights in the Travel Planning dataset. If I understand correct. Both "city A and city B" as well as "from city A to city B", means a **single directional connection** right?

According to issue #1 I understand from "city A to city B" means single directional connection, I just want to confirm "A and B" also means single directional connection.

If not, it seems there are some examples having multiple solutions like (the 459-th example)

```
You plan to visit 5 European cities for 19 days in total. You only take direct flights to commute between cities. You would like to visit Zurich for 6 days. During day 7 and day 12, you have to attend a conference in Zurich. You want to spend 4 days in Athens. You want to spend 7 days in Dubrovnik. You plan to stay in Stuttgart for 4 days. You plan to stay in Manchester for 2 days. You would like to meet your friends at Manchester between day 18 and day 19 to tour together.

Here are the cities that have direct flights:
Athens and Manchester, Stuttgart and Athens, Athens and Zurich, Zurich and Dubrovnik, Stuttgart and Manchester, Dubrovnik and Manchester, Athens and Dubrovnik, Zurich and Manchester.

Find a trip plan of visiting the cities for 19 days by taking direct flights to commute between them.
------Alterative Solution----------
**Day 1-7:** Arriving in Dubrovnik and visit Dubrovnik for 7 days.
**Day 7:** Fly from Dubrovnik to Zurich.
**Day 7-12:** Visit Zurich for 6 days.
**Day 12:** Fly from Zurich to Athens.
**Day 12-15:** Visit Athens for 4 days.
**Day 15:** Fly from Athens to Stuttgart.
**Day 15-18:** Visit Stuttgart for 4 days.
**Day 18:** Fly from Stuttgart to Manchester.
**Day 18-19:** Visit Manchester for 2 days.

------Gold----------
Here is the trip plan for visiting the 5 European cities for 19 days:

**Day 1-4:** Arriving in Stuttgart and visit Stuttgart for 4 days.
**Day 4:** Fly from Stuttgart to Athens.
**Day 4-7:** Visit Athens for 4 days.
**Day 7:** Fly from Athens to Zurich.
**Day 7-12:** Visit Zurich for 6 days.
**Day 12:** Fly from Zurich to Dubrovnik.
**Day 12-18:** Visit Dubrovnik for 7 days.
**Day 18:** Fly from Dubrovnik to Manchester.
**Day 18-19:** Visit Manchester for 2 days.
```

Review the Travel Planning dataset wording and the interpretation referenced in issue #1. Determine whether “city A and city B” denotes a directional connection, then check example 459 for whether that interpretation removes the alternative solution; document the confirmed semantics if needed.

Written by the indexing model from the issue text.