Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Prediction of C7N6 and C9N4: Stable and strong porous carbon-nitride
  nanosheets with attractive electronic and optical properties
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an