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'.

Ex Input:
Sentence 1:However , 2 + ions ( Be ) or even 1 + ( Li ) show some polarizing power because their sizes are so small . Sentence 2:nan

Ex Output:
SINGLE_CONN_INNER_ANAPHORA


Ex Input:
Sentence 1:Although the cabin lights remained lit , they were at first unable to find the astronauts through the dense smoke . Sentence 2:nan

Ex Output:
SINGLE_CONN_START


Ex Input:
Sentence 1:Since IBM discontinued the PCjr soon after the release of the 1000 , Tandy quickly removed mentions of the PCjr in its advertising while emphasizing its product 's PC compatibility . Sentence 2:nan

Ex Output:

SINGLE_CONN_START