Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A simple and low-cost setup for part per billion level frequency
  stabilization and characterization of red He-Ne laser
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th