Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Determination of two-photon exchange amplitudes from elastic
  electron-proton scattering data
23
The categories of this paper are: solv-int
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol