You are a helpful assistant. The assistant first thinks about the reasoning process in the mind and then provides the user with the answer. The reasoning process and answer must be formatted exactly as follows:
<think>
[your reasoning process here]
</think>
<answer>
[your answer here]
</answer>
You can choose to imitate the reasoning process of relevant algorithms or explore an appropriate solution on your own. DO NOT use code, and remember to focus on the logical flow.
system
You are required to solve the Travelling Salesman Problem for an undirected flight route network. Your objective is to determine the shortest possible route that visits each of the listed airports exactly once and returns to the starting point.

**Problem to Solve**

- Airports to visit: SFJ, XNA, KTT, AQJ, TVC, SGY, ZAZ, BHJ, ZTB
- Travel distances (in kilometers) between each pair of airports:
SFJ to XNA: 7379
SFJ to BHJ: 10484
SFJ to TVC: 6563
SFJ to KTT: 4981
SFJ to ZAZ: 4742
SFJ to SGY: 9117
SFJ to AQJ: 6817
SFJ to ZTB: 7266
XNA to BHJ: 14570
XNA to TVC: 1198
XNA to KTT: 8912
XNA to ZAZ: 8344
XNA to SGY: 4223
XNA to AQJ: 11031
XNA to ZTB: 3259
KTT to BHJ: 7575
KTT to TVC: 8110
KTT to ZAZ: 3707
KTT to SGY: 10664
KTT to AQJ: 4353
KTT to ZTB: 7127
AQJ to BHJ: 4761
AQJ to TVC: 10243
AQJ to ZAZ: 3870
AQJ to SGY: 12923
AQJ to ZTB: 8349
TVC to BHJ: 13792
TVC to ZAZ: 7546
TVC to SGY: 4434
TVC to ZTB: 2443
SGY to BHJ: 15626
SGY to ZAZ: 10425
SGY to ZTB: 6586
ZAZ to BHJ: 7986
ZAZ to ZTB: 6130
BHJ to ZTB: 12244
Please calculate the shortest tour and format your answer as follows: [Airport A, Airport B, Airport C, ..., Airport A]
user
{"directed": false, "multigraph": false, "graph": {}, "nodes": [{"name": "SFJ", "id": 0}, {"name": "XNA", "id": 1}, {"name": "KTT", "id": 2}, {"name": "AQJ", "id": 3}, {"name": "TVC", "id": 4}, {"name": "SGY", "id": 5}, {"name": "ZAZ", "id": 6}, {"name": "BHJ", "id": 7}, {"name": "ZTB", "id": 8}], "links": [{"weight": 7379, "source": 0, "target": 1}, {"weight": 10484, "source": 0, "target": 7}, {"weight": 6563, "source": 0, "target": 4}, {"weight": 4981, "source": 0, "target": 2}, {"weight": 4742, "source": 0, "target": 6}, {"weight": 9117, "source": 0, "target": 5}, {"weight": 6817, "source": 0, "target": 3}, {"weight": 7266, "source": 0, "target": 8}, {"weight": 14570, "source": 1, "target": 7}, {"weight": 1198, "source": 1, "target": 4}, {"weight": 8912, "source": 1, "target": 2}, {"weight": 8344, "source": 1, "target": 6}, {"weight": 4223, "source": 1, "target": 5}, {"weight": 11031, "source": 1, "target": 3}, {"weight": 3259, "source": 1, "target": 8}, {"weight": 7575, "source": 2, "target": 7}, {"weight": 8110, "source": 2, "target": 4}, {"weight": 3707, "source": 2, "target": 6}, {"weight": 10664, "source": 2, "target": 5}, {"weight": 4353, "source": 2, "target": 3}, {"weight": 7127, "source": 2, "target": 8}, {"weight": 4761, "source": 3, "target": 7}, {"weight": 10243, "source": 3, "target": 4}, {"weight": 3870, "source": 3, "target": 6}, {"weight": 12923, "source": 3, "target": 5}, {"weight": 8349, "source": 3, "target": 8}, {"weight": 13792, "source": 4, "target": 7}, {"weight": 7546, "source": 4, "target": 6}, {"weight": 4434, "source": 4, "target": 5}, {"weight": 2443, "source": 4, "target": 8}, {"weight": 15626, "source": 5, "target": 7}, {"weight": 10425, "source": 5, "target": 6}, {"weight": 6586, "source": 5, "target": 8}, {"weight": 7986, "source": 6, "target": 7}, {"weight": 6130, "source": 6, "target": 8}, {"weight": 12244, "source": 7, "target": 8}]}
You are required to solve the Travelling Salesman Problem for an undirected flight route network. Your objective is to determine the shortest possible route that visits each of the listed airports exactly once and returns to the starting point.

**Problem to Solve**

- Airports to visit: SFJ, XNA, KTT, AQJ, TVC, SGY, ZAZ, BHJ, ZTB
- Travel distances (in kilometers) between each pair of airports:
SFJ to XNA: 7379
SFJ to BHJ: 10484
SFJ to TVC: 6563
SFJ to KTT: 4981
SFJ to ZAZ: 4742
SFJ to SGY: 9117
SFJ to AQJ: 6817
SFJ to ZTB: 7266
XNA to BHJ: 14570
XNA to TVC: 1198
XNA to KTT: 8912
XNA to ZAZ: 8344
XNA to SGY: 4223
XNA to AQJ: 11031
XNA to ZTB: 3259
KTT to BHJ: 7575
KTT to TVC: 8110
KTT to ZAZ: 3707
KTT to SGY: 10664
KTT to AQJ: 4353
KTT to ZTB: 7127
AQJ to BHJ: 4761
AQJ to TVC: 10243
AQJ to ZAZ: 3870
AQJ to SGY: 12923
AQJ to ZTB: 8349
TVC to BHJ: 13792
TVC to ZAZ: 7546
TVC to SGY: 4434
TVC to ZTB: 2443
SGY to BHJ: 15626
SGY to ZAZ: 10425
SGY to ZTB: 6586
ZAZ to BHJ: 7986
ZAZ to ZTB: 6130
BHJ to ZTB: 12244
Please calculate the shortest tour and format your answer as follows: [Airport A, Airport B, Airport C, ..., Airport A]
test