<|im_start|>system
Please reason step by step, and put your final answer within \boxed{}.<|im_end|>
<|im_start|>user
Given the following crystal representation:
12.1 12.1 12.1
15 15 15
Zr
0.00 0.00 0.56
Zr
0.00 0.00 0.21
Ag
0.00 0.00 0.57
Ag
0.00 0.00 0.00
Ag
0.00 0.00 0.20
Identify the crystal system.<|im_end|>
<|im_start|>assistant
Given the following crystal representation:
12.1 12.1 12.1
15 15 15
Zr
0.00 0.00 0.56
Zr
0.00 0.00 0.21
Ag
0.00 0.00 0.57
Ag
0.00 0.00 0.00
Ag
0.00 0.00 0.20
Identify the crystal system.