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: NAO, WUX, CLT, SAF, CRM, CCJ, ABE, TTA, KPV
- Travel distances (in kilometers) between each pair of airports:
NAO to CRM: 2813
NAO to WUX: 1618
NAO to CLT: 12858
NAO to CCJ: 4037
NAO to ABE: 12590
NAO to SAF: 12175
NAO to TTA: 11198
NAO to KPV: 13214
WUX to CRM: 2342
WUX to CLT: 12466
WUX to CCJ: 5205
WUX to ABE: 12198
WUX to SAF: 11439
WUX to TTA: 11695
WUX to KPV: 12495
CLT to ABE: 773
CLT to CRM: 14517
CLT to CCJ: 14337
CLT to SAF: 2386
CLT to TTA: 7203
CLT to KPV: 6336
SAF to CRM: 13281
SAF to CCJ: 15699
SAF to ABE: 2963
SAF to TTA: 9300
SAF to KPV: 5155
CRM to CCJ: 5365
CRM to ABE: 14319
CRM to TTA: 13497
CRM to KPV: 14249
CCJ to ABE: 13705
CCJ to TTA: 9379
CCJ to KPV: 17241
ABE to TTA: 6571
ABE to KPV: 6374
TTA to KPV: 12636
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": "NAO", "id": 0}, {"name": "WUX", "id": 1}, {"name": "CLT", "id": 2}, {"name": "SAF", "id": 3}, {"name": "CRM", "id": 4}, {"name": "CCJ", "id": 5}, {"name": "ABE", "id": 6}, {"name": "TTA", "id": 7}, {"name": "KPV", "id": 8}], "links": [{"weight": 2813, "source": 0, "target": 4}, {"weight": 1618, "source": 0, "target": 1}, {"weight": 12858, "source": 0, "target": 2}, {"weight": 4037, "source": 0, "target": 5}, {"weight": 12590, "source": 0, "target": 6}, {"weight": 12175, "source": 0, "target": 3}, {"weight": 11198, "source": 0, "target": 7}, {"weight": 13214, "source": 0, "target": 8}, {"weight": 2342, "source": 1, "target": 4}, {"weight": 12466, "source": 1, "target": 2}, {"weight": 5205, "source": 1, "target": 5}, {"weight": 12198, "source": 1, "target": 6}, {"weight": 11439, "source": 1, "target": 3}, {"weight": 11695, "source": 1, "target": 7}, {"weight": 12495, "source": 1, "target": 8}, {"weight": 773, "source": 2, "target": 6}, {"weight": 14517, "source": 2, "target": 4}, {"weight": 14337, "source": 2, "target": 5}, {"weight": 2386, "source": 2, "target": 3}, {"weight": 7203, "source": 2, "target": 7}, {"weight": 6336, "source": 2, "target": 8}, {"weight": 13281, "source": 3, "target": 4}, {"weight": 15699, "source": 3, "target": 5}, {"weight": 2963, "source": 3, "target": 6}, {"weight": 9300, "source": 3, "target": 7}, {"weight": 5155, "source": 3, "target": 8}, {"weight": 5365, "source": 4, "target": 5}, {"weight": 14319, "source": 4, "target": 6}, {"weight": 13497, "source": 4, "target": 7}, {"weight": 14249, "source": 4, "target": 8}, {"weight": 13705, "source": 5, "target": 6}, {"weight": 9379, "source": 5, "target": 7}, {"weight": 17241, "source": 5, "target": 8}, {"weight": 6571, "source": 6, "target": 7}, {"weight": 6374, "source": 6, "target": 8}, {"weight": 12636, "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: NAO, WUX, CLT, SAF, CRM, CCJ, ABE, TTA, KPV
- Travel distances (in kilometers) between each pair of airports:
NAO to CRM: 2813
NAO to WUX: 1618
NAO to CLT: 12858
NAO to CCJ: 4037
NAO to ABE: 12590
NAO to SAF: 12175
NAO to TTA: 11198
NAO to KPV: 13214
WUX to CRM: 2342
WUX to CLT: 12466
WUX to CCJ: 5205
WUX to ABE: 12198
WUX to SAF: 11439
WUX to TTA: 11695
WUX to KPV: 12495
CLT to ABE: 773
CLT to CRM: 14517
CLT to CCJ: 14337
CLT to SAF: 2386
CLT to TTA: 7203
CLT to KPV: 6336
SAF to CRM: 13281
SAF to CCJ: 15699
SAF to ABE: 2963
SAF to TTA: 9300
SAF to KPV: 5155
CRM to CCJ: 5365
CRM to ABE: 14319
CRM to TTA: 13497
CRM to KPV: 14249
CCJ to ABE: 13705
CCJ to TTA: 9379
CCJ to KPV: 17241
ABE to TTA: 6571
ABE to KPV: 6374
TTA to KPV: 12636
Please calculate the shortest tour and format your answer as follows: [Airport A, Airport B, Airport C, ..., Airport A]
test