Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Massive migration from the steppe is a source for Indo-European
  languages in Europe
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th