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: TWU, CGM, ENE, INL, HEH, CLD, XCR, YFJ, ORY
- Travel distances (in kilometers) between each pair of airports:
TWU to CGM: 1524
TWU to HEH: 3333
TWU to YFJ: 13834
TWU to ORY: 11736
TWU to INL: 14396
TWU to XCR: 14165
TWU to ENE: 2211
TWU to CLD: 13265
CGM to HEH: 3930
CGM to YFJ: 12819
CGM to ORY: 11467
CGM to INL: 13381
CGM to XCR: 13969
CGM to ENE: 3585
CGM to CLD: 12311
ENE to HEH: 4718
ENE to YFJ: 15726
ENE to ORY: 13143
ENE to INL: 16288
ENE to XCR: 15488
ENE to CLD: 15218
INL to HEH: 14236
INL to YFJ: 3363
INL to ORY: 7218
INL to XCR: 8451
INL to CLD: 3014
HEH to YFJ: 13543
HEH to ORY: 9387
HEH to XCR: 11727
HEH to CLD: 13206
CLD to YFJ: 3534
CLD to ORY: 9264
CLD to XCR: 10585
XCR to YFJ: 10264
XCR to ORY: 2512
YFJ to ORY: 8386
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": "TWU", "id": 0}, {"name": "CGM", "id": 1}, {"name": "ENE", "id": 2}, {"name": "INL", "id": 3}, {"name": "HEH", "id": 4}, {"name": "CLD", "id": 5}, {"name": "XCR", "id": 6}, {"name": "YFJ", "id": 7}, {"name": "ORY", "id": 8}], "links": [{"weight": 1524, "source": 0, "target": 1}, {"weight": 3333, "source": 0, "target": 4}, {"weight": 13834, "source": 0, "target": 7}, {"weight": 11736, "source": 0, "target": 8}, {"weight": 14396, "source": 0, "target": 3}, {"weight": 14165, "source": 0, "target": 6}, {"weight": 2211, "source": 0, "target": 2}, {"weight": 13265, "source": 0, "target": 5}, {"weight": 3930, "source": 1, "target": 4}, {"weight": 12819, "source": 1, "target": 7}, {"weight": 11467, "source": 1, "target": 8}, {"weight": 13381, "source": 1, "target": 3}, {"weight": 13969, "source": 1, "target": 6}, {"weight": 3585, "source": 1, "target": 2}, {"weight": 12311, "source": 1, "target": 5}, {"weight": 4718, "source": 2, "target": 4}, {"weight": 15726, "source": 2, "target": 7}, {"weight": 13143, "source": 2, "target": 8}, {"weight": 16288, "source": 2, "target": 3}, {"weight": 15488, "source": 2, "target": 6}, {"weight": 15218, "source": 2, "target": 5}, {"weight": 14236, "source": 3, "target": 4}, {"weight": 3363, "source": 3, "target": 7}, {"weight": 7218, "source": 3, "target": 8}, {"weight": 8451, "source": 3, "target": 6}, {"weight": 3014, "source": 3, "target": 5}, {"weight": 13543, "source": 4, "target": 7}, {"weight": 9387, "source": 4, "target": 8}, {"weight": 11727, "source": 4, "target": 6}, {"weight": 13206, "source": 4, "target": 5}, {"weight": 3534, "source": 5, "target": 7}, {"weight": 9264, "source": 5, "target": 8}, {"weight": 10585, "source": 5, "target": 6}, {"weight": 10264, "source": 6, "target": 7}, {"weight": 2512, "source": 6, "target": 8}, {"weight": 8386, "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: TWU, CGM, ENE, INL, HEH, CLD, XCR, YFJ, ORY
- Travel distances (in kilometers) between each pair of airports:
TWU to CGM: 1524
TWU to HEH: 3333
TWU to YFJ: 13834
TWU to ORY: 11736
TWU to INL: 14396
TWU to XCR: 14165
TWU to ENE: 2211
TWU to CLD: 13265
CGM to HEH: 3930
CGM to YFJ: 12819
CGM to ORY: 11467
CGM to INL: 13381
CGM to XCR: 13969
CGM to ENE: 3585
CGM to CLD: 12311
ENE to HEH: 4718
ENE to YFJ: 15726
ENE to ORY: 13143
ENE to INL: 16288
ENE to XCR: 15488
ENE to CLD: 15218
INL to HEH: 14236
INL to YFJ: 3363
INL to ORY: 7218
INL to XCR: 8451
INL to CLD: 3014
HEH to YFJ: 13543
HEH to ORY: 9387
HEH to XCR: 11727
HEH to CLD: 13206
CLD to YFJ: 3534
CLD to ORY: 9264
CLD to XCR: 10585
XCR to YFJ: 10264
XCR to ORY: 2512
YFJ to ORY: 8386
Please calculate the shortest tour and format your answer as follows: [Airport A, Airport B, Airport C, ..., Airport A]
test