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: ACR, IXZ, MCT, ANI, YRB, FKS, GRI, JSY, YYC
- Travel distances (in kilometers) between each pair of airports:
ACR to MCT: 14616
ACR to YRB: 8797
ACR to YYC: 6974
ACR to ANI: 9944
ACR to IXZ: 18295
ACR to JSY: 11117
ACR to GRI: 5443
ACR to FKS: 15842
IXZ to MCT: 3961
IXZ to YRB: 16991
IXZ to YYC: 14073
IXZ to ANI: 16409
IXZ to JSY: 7589
IXZ to GRI: 16528
IXZ to FKS: 6625
MCT to YRB: 13609
MCT to YYC: 12391
MCT to ANI: 15110
MCT to JSY: 3724
MCT to GRI: 14132
MCT to FKS: 8099
ANI to YRB: 8641
ANI to YYC: 3560
ANI to JSY: 12952
ANI to GRI: 5772
ANI to FKS: 11473
YRB to YYC: 5152
YRB to JSY: 10307
YRB to GRI: 6872
YRB to FKS: 14083
FKS to YYC: 8931
FKS to JSY: 10059
FKS to GRI: 11435
GRI to YYC: 3233
GRI to JSY: 11061
JSY to YYC: 9448
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": "ACR", "id": 0}, {"name": "IXZ", "id": 1}, {"name": "MCT", "id": 2}, {"name": "ANI", "id": 3}, {"name": "YRB", "id": 4}, {"name": "FKS", "id": 5}, {"name": "GRI", "id": 6}, {"name": "JSY", "id": 7}, {"name": "YYC", "id": 8}], "links": [{"weight": 14616, "source": 0, "target": 2}, {"weight": 8797, "source": 0, "target": 4}, {"weight": 6974, "source": 0, "target": 8}, {"weight": 9944, "source": 0, "target": 3}, {"weight": 18295, "source": 0, "target": 1}, {"weight": 11117, "source": 0, "target": 7}, {"weight": 5443, "source": 0, "target": 6}, {"weight": 15842, "source": 0, "target": 5}, {"weight": 3961, "source": 1, "target": 2}, {"weight": 16991, "source": 1, "target": 4}, {"weight": 14073, "source": 1, "target": 8}, {"weight": 16409, "source": 1, "target": 3}, {"weight": 7589, "source": 1, "target": 7}, {"weight": 16528, "source": 1, "target": 6}, {"weight": 6625, "source": 1, "target": 5}, {"weight": 13609, "source": 2, "target": 4}, {"weight": 12391, "source": 2, "target": 8}, {"weight": 15110, "source": 2, "target": 3}, {"weight": 3724, "source": 2, "target": 7}, {"weight": 14132, "source": 2, "target": 6}, {"weight": 8099, "source": 2, "target": 5}, {"weight": 8641, "source": 3, "target": 4}, {"weight": 3560, "source": 3, "target": 8}, {"weight": 12952, "source": 3, "target": 7}, {"weight": 5772, "source": 3, "target": 6}, {"weight": 11473, "source": 3, "target": 5}, {"weight": 5152, "source": 4, "target": 8}, {"weight": 10307, "source": 4, "target": 7}, {"weight": 6872, "source": 4, "target": 6}, {"weight": 14083, "source": 4, "target": 5}, {"weight": 8931, "source": 5, "target": 8}, {"weight": 10059, "source": 5, "target": 7}, {"weight": 11435, "source": 5, "target": 6}, {"weight": 3233, "source": 6, "target": 8}, {"weight": 11061, "source": 6, "target": 7}, {"weight": 9448, "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: ACR, IXZ, MCT, ANI, YRB, FKS, GRI, JSY, YYC
- Travel distances (in kilometers) between each pair of airports:
ACR to MCT: 14616
ACR to YRB: 8797
ACR to YYC: 6974
ACR to ANI: 9944
ACR to IXZ: 18295
ACR to JSY: 11117
ACR to GRI: 5443
ACR to FKS: 15842
IXZ to MCT: 3961
IXZ to YRB: 16991
IXZ to YYC: 14073
IXZ to ANI: 16409
IXZ to JSY: 7589
IXZ to GRI: 16528
IXZ to FKS: 6625
MCT to YRB: 13609
MCT to YYC: 12391
MCT to ANI: 15110
MCT to JSY: 3724
MCT to GRI: 14132
MCT to FKS: 8099
ANI to YRB: 8641
ANI to YYC: 3560
ANI to JSY: 12952
ANI to GRI: 5772
ANI to FKS: 11473
YRB to YYC: 5152
YRB to JSY: 10307
YRB to GRI: 6872
YRB to FKS: 14083
FKS to YYC: 8931
FKS to JSY: 10059
FKS to GRI: 11435
GRI to YYC: 3233
GRI to JSY: 11061
JSY to YYC: 9448
Please calculate the shortest tour and format your answer as follows: [Airport A, Airport B, Airport C, ..., Airport A]
test