Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: South African Riots: Repercussion of the Global Food Crisis and US
  Drought
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th