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:In this article , he explains that although the Book of Mormon Index page used to say that the River Sidon flowed North . Sentence 2:nan
Example Output: SINGLE_CONN_INNER

Example Input: Sentence 1:PA 436 was assigned in the 1928 numbering of roads in Pennsylvania and not paved until 1932 . Sentence 2:The road 's other lone major intersection on PA 436 is for Jefferson SR 3012 .
Example Output: PAIR_ANAPHORA

Example Input: Sentence 1:David Nabarro , the newly appointed Senior United Nations System Coordinator for Avian and Human Influenza , warned the world that an outbreak of avian influenza could kill 5 to 150 million people . Sentence 2:nan
Example Output:
SINGLE_APPOSITION