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Example Input: Sentence 1:Although most of his work went unpublished , Taylor was the first psychologist known to use exposure therapy treatment for anxiety , including methods of situational exposure with response prevention -- a common exposure therapy technique still being used . Sentence 2:nan
Example Output: SINGLE_CONN_START

Example Input: Sentence 1:Jackie returned to find the Franchetti mob taken over by Frankie 's cousin , Paulie . Sentence 2:Paulie was able to discover Jackie 's secret , and Paulie blackmailed Jackie into doing hits for him .
Example Output: PAIR_ANAPHORA

Example Input: Sentence 1:Inveneo , the company that NetHope tapped to build the network , defended the action by saying that in the days after the earthquake it was critical for NGOs to have reliable connectivity in order to coordinate their actions using resources such as Google Maps . Sentence 2:nan
Example Output:
SINGLE_APPOSITION