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:The YouTube app , which had been a default app on iOS developed by Apple , was removed . Sentence 2:nan
answer:
SINGLE_RELATIVE


question:
Sentence 1:They work in groups consisting of on average 2 - 4 people , sharing work equally . Sentence 2:They use resources such as internet , PowerPoint presentations and videos to learn , instead of a teacher standing up in front of the room doing a lecture every day .
answer:
PAIR_NONE


question:
Sentence 1:Going back to general quarters for the dawn alert at 0525 on the 29th , Bunch spotted planes at 0605 , but they remained out of range . Sentence 2:nan
answer:

SINGLE_CATAPHORA