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: SXB, DJB, CHX, BTV, EPR, VNO, KUO, TPA, MYA
- Travel distances (in kilometers) between each pair of airports:
SXB to TPA: 7742
SXB to CHX: 9639
SXB to BTV: 6610
SXB to VNO: 1411
SXB to KUO: 2163
SXB to DJB: 10957
SXB to EPR: 14594
SXB to MYA: 16857
DJB to TPA: 17377
DJB to CHX: 19384
DJB to BTV: 16581
DJB to VNO: 9567
DJB to KUO: 9976
DJB to EPR: 4209
DJB to MYA: 6355
CHX to TPA: 2390
CHX to BTV: 4234
CHX to VNO: 10715
CHX to KUO: 10741
CHX to EPR: 20359
CHX to MYA: 16864
BTV to TPA: 2014
BTV to VNO: 7378
BTV to KUO: 7363
BTV to EPR: 19746
BTV to MYA: 16323
EPR to TPA: 19043
EPR to VNO: 13647
EPR to KUO: 14056
EPR to MYA: 3848
VNO to TPA: 8568
VNO to KUO: 965
VNO to MYA: 15541
KUO to TPA: 8560
KUO to MYA: 15773
TPA to MYA: 15537
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": "SXB", "id": 0}, {"name": "DJB", "id": 1}, {"name": "CHX", "id": 2}, {"name": "BTV", "id": 3}, {"name": "EPR", "id": 4}, {"name": "VNO", "id": 5}, {"name": "KUO", "id": 6}, {"name": "TPA", "id": 7}, {"name": "MYA", "id": 8}], "links": [{"weight": 7742, "source": 0, "target": 7}, {"weight": 9639, "source": 0, "target": 2}, {"weight": 6610, "source": 0, "target": 3}, {"weight": 1411, "source": 0, "target": 5}, {"weight": 2163, "source": 0, "target": 6}, {"weight": 10957, "source": 0, "target": 1}, {"weight": 14594, "source": 0, "target": 4}, {"weight": 16857, "source": 0, "target": 8}, {"weight": 17377, "source": 1, "target": 7}, {"weight": 19384, "source": 1, "target": 2}, {"weight": 16581, "source": 1, "target": 3}, {"weight": 9567, "source": 1, "target": 5}, {"weight": 9976, "source": 1, "target": 6}, {"weight": 4209, "source": 1, "target": 4}, {"weight": 6355, "source": 1, "target": 8}, {"weight": 2390, "source": 2, "target": 7}, {"weight": 4234, "source": 2, "target": 3}, {"weight": 10715, "source": 2, "target": 5}, {"weight": 10741, "source": 2, "target": 6}, {"weight": 20359, "source": 2, "target": 4}, {"weight": 16864, "source": 2, "target": 8}, {"weight": 2014, "source": 3, "target": 7}, {"weight": 7378, "source": 3, "target": 5}, {"weight": 7363, "source": 3, "target": 6}, {"weight": 19746, "source": 3, "target": 4}, {"weight": 16323, "source": 3, "target": 8}, {"weight": 19043, "source": 4, "target": 7}, {"weight": 13647, "source": 4, "target": 5}, {"weight": 14056, "source": 4, "target": 6}, {"weight": 3848, "source": 4, "target": 8}, {"weight": 8568, "source": 5, "target": 7}, {"weight": 965, "source": 5, "target": 6}, {"weight": 15541, "source": 5, "target": 8}, {"weight": 8560, "source": 6, "target": 7}, {"weight": 15773, "source": 6, "target": 8}, {"weight": 15537, "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: SXB, DJB, CHX, BTV, EPR, VNO, KUO, TPA, MYA
- Travel distances (in kilometers) between each pair of airports:
SXB to TPA: 7742
SXB to CHX: 9639
SXB to BTV: 6610
SXB to VNO: 1411
SXB to KUO: 2163
SXB to DJB: 10957
SXB to EPR: 14594
SXB to MYA: 16857
DJB to TPA: 17377
DJB to CHX: 19384
DJB to BTV: 16581
DJB to VNO: 9567
DJB to KUO: 9976
DJB to EPR: 4209
DJB to MYA: 6355
CHX to TPA: 2390
CHX to BTV: 4234
CHX to VNO: 10715
CHX to KUO: 10741
CHX to EPR: 20359
CHX to MYA: 16864
BTV to TPA: 2014
BTV to VNO: 7378
BTV to KUO: 7363
BTV to EPR: 19746
BTV to MYA: 16323
EPR to TPA: 19043
EPR to VNO: 13647
EPR to KUO: 14056
EPR to MYA: 3848
VNO to TPA: 8568
VNO to KUO: 965
VNO to MYA: 15541
KUO to TPA: 8560
KUO to MYA: 15773
TPA to MYA: 15537
Please calculate the shortest tour and format your answer as follows: [Airport A, Airport B, Airport C, ..., Airport A]
test