instruction:
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'.
question:
Sentence 1:Liz realizes that she needs to take control of her personal life by fixing up her dream apartment , but she encounters an obstacle along the way . Sentence 2:Meanwhile , Jack has his own problems to deal with when Avery is held hostage .
answer:
PAIR_CONN


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


question:
Sentence 1:The building , which stretches along the Mechitaristengasse , has four floors . Sentence 2:nan
answer:

SINGLE_RELATIVE