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: KTA, CMP, DPO, DIE, KRN, OSS, OLH, GLN, XEQ
- Travel distances (in kilometers) between each pair of airports:
KTA to OLH: 16257
KTA to GLN: 15668
KTA to OSS: 9015
KTA to KRN: 13710
KTA to XEQ: 16873
KTA to DIE: 8525
KTA to DPO: 3703
KTA to CMP: 19579
CMP to OLH: 12301
CMP to GLN: 6729
CMP to OSS: 14091
CMP to KRN: 11367
CMP to XEQ: 12406
CMP to DIE: 12895
CMP to DPO: 17647
DPO to OLH: 14240
DPO to GLN: 18637
DPO to OSS: 12231
DPO to KRN: 16929
DPO to XEQ: 20089
DPO to DIE: 10385
DIE to OLH: 19331
DIE to GLN: 9271
DIE to OSS: 8197
DIE to KRN: 9871
DIE to XEQ: 12749
KRN to OLH: 11674
KRN to GLN: 4903
KRN to OSS: 5212
KRN to XEQ: 5080
OSS to OLH: 14966
OSS to GLN: 7501
OSS to XEQ: 8372
OLH to GLN: 12188
OLH to XEQ: 10640
GLN to XEQ: 6457
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": "KTA", "id": 0}, {"name": "CMP", "id": 1}, {"name": "DPO", "id": 2}, {"name": "DIE", "id": 3}, {"name": "KRN", "id": 4}, {"name": "OSS", "id": 5}, {"name": "OLH", "id": 6}, {"name": "GLN", "id": 7}, {"name": "XEQ", "id": 8}], "links": [{"weight": 16257, "source": 0, "target": 6}, {"weight": 15668, "source": 0, "target": 7}, {"weight": 9015, "source": 0, "target": 5}, {"weight": 13710, "source": 0, "target": 4}, {"weight": 16873, "source": 0, "target": 8}, {"weight": 8525, "source": 0, "target": 3}, {"weight": 3703, "source": 0, "target": 2}, {"weight": 19579, "source": 0, "target": 1}, {"weight": 12301, "source": 1, "target": 6}, {"weight": 6729, "source": 1, "target": 7}, {"weight": 14091, "source": 1, "target": 5}, {"weight": 11367, "source": 1, "target": 4}, {"weight": 12406, "source": 1, "target": 8}, {"weight": 12895, "source": 1, "target": 3}, {"weight": 17647, "source": 1, "target": 2}, {"weight": 14240, "source": 2, "target": 6}, {"weight": 18637, "source": 2, "target": 7}, {"weight": 12231, "source": 2, "target": 5}, {"weight": 16929, "source": 2, "target": 4}, {"weight": 20089, "source": 2, "target": 8}, {"weight": 10385, "source": 2, "target": 3}, {"weight": 19331, "source": 3, "target": 6}, {"weight": 9271, "source": 3, "target": 7}, {"weight": 8197, "source": 3, "target": 5}, {"weight": 9871, "source": 3, "target": 4}, {"weight": 12749, "source": 3, "target": 8}, {"weight": 11674, "source": 4, "target": 6}, {"weight": 4903, "source": 4, "target": 7}, {"weight": 5212, "source": 4, "target": 5}, {"weight": 5080, "source": 4, "target": 8}, {"weight": 14966, "source": 5, "target": 6}, {"weight": 7501, "source": 5, "target": 7}, {"weight": 8372, "source": 5, "target": 8}, {"weight": 12188, "source": 6, "target": 7}, {"weight": 10640, "source": 6, "target": 8}, {"weight": 6457, "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: KTA, CMP, DPO, DIE, KRN, OSS, OLH, GLN, XEQ
- Travel distances (in kilometers) between each pair of airports:
KTA to OLH: 16257
KTA to GLN: 15668
KTA to OSS: 9015
KTA to KRN: 13710
KTA to XEQ: 16873
KTA to DIE: 8525
KTA to DPO: 3703
KTA to CMP: 19579
CMP to OLH: 12301
CMP to GLN: 6729
CMP to OSS: 14091
CMP to KRN: 11367
CMP to XEQ: 12406
CMP to DIE: 12895
CMP to DPO: 17647
DPO to OLH: 14240
DPO to GLN: 18637
DPO to OSS: 12231
DPO to KRN: 16929
DPO to XEQ: 20089
DPO to DIE: 10385
DIE to OLH: 19331
DIE to GLN: 9271
DIE to OSS: 8197
DIE to KRN: 9871
DIE to XEQ: 12749
KRN to OLH: 11674
KRN to GLN: 4903
KRN to OSS: 5212
KRN to XEQ: 5080
OSS to OLH: 14966
OSS to GLN: 7501
OSS to XEQ: 8372
OLH to GLN: 12188
OLH to XEQ: 10640
GLN to XEQ: 6457
Please calculate the shortest tour and format your answer as follows: [Airport A, Airport B, Airport C, ..., Airport A]
test