Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Photoproduction of pi0pi0 and pi0pi+-pairs off the proton from threshold
  to the second resonance region
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
2
The categories of this paper are: math
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an