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:Some evidence suggests that Barbados may have been settled in the second millennium BC , but this is limited to fragments of conch lip adzes found in association with shells that have been radiocarbon - dated to about 1630 BC . Sentence 2:nan
Example Output: SINGLE_S_COORD

Example Input: Sentence 1:Friends and colleagues met Williams in Europe , with the last meetings occurring in the mid 1970s in Salzburg , Austria . Sentence 2:In 1972 , he accepted and then later declined a post at the Latter Day Saints Hospital in Salt Lake City Utah , United States .
Example Output: PAIR_ANAPHORA

Example Input: Sentence 1:Marco Cecchinato was the defending champion but chose not to participate . Sentence 2:nan
Example Output:
SINGLE_VP_COORD