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:Galvanized steel offers more protection from rust , so this is usually used when the gusset plate is exposed to the elements . Sentence 2:nan
Example Output: SINGLE_S_COORD

Example Input: Sentence 1:O'Donnell was the starter for the first six games of the season , but they went 0 -- 6 under him . Sentence 2:nan
Example Output: SINGLE_S_COORD_ANAPHORA

Example Input: Sentence 1:Tracking the ship , they find it has been attacked with a complete loss of life , and all of its supplies , including those belonging to Voyager are gone . Sentence 2:nan
Example Output:
SINGLE_CATAPHORA