In this task, you are given two sentences in the English language and your task is to classify them into one of their discourse types. A discourse type is an indicator to classify the given two sentences on the basis of a co-text as well as a relevant context. There are 13 discourse types in total which are 'SINGLE_S_COORD', 'SINGLE_CATAPHORA', 'SINGLE_CONN_INNER', 'SINGLE_APPOSITION', 'SINGLE_VP_COORD', 'SINGLE_CONN_START', 'PAIR_ANAPHORA', 'PAIR_CONN', 'SINGLE_RELATIVE', 'SINGLE_CONN_INNER_ANAPHORA', 'SINGLE_S_COORD_ANAPHORA', 'PAIR_CONN_ANAPHORA' and 'PAIR_NONE'.

Example Input: Sentence 1:It is the most historic area of Derby , the location of a large fortified Roman settlement , which they called Derventio . Sentence 2:nan
Example Output: SINGLE_APPOSITION

Example Input: Sentence 1:In April 1933 , Farnsworth submitted a patent application entitled Image Dissector , but which actually detailed a cathode ray tube ( CRT ) camera tube . Sentence 2:nan
Example Output: SINGLE_S_COORD

Example Input: Sentence 1:Nagy 's search for a new physics , which will lead to a new means of space travel , is helped by Schwoerin 's research . Sentence 2:nan
Example Output:
SINGLE_RELATIVE