Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Simulations of shell galaxies with GADGET-2: Multi-generation shell
  systems
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph