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'.

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

A: SINGLE_CONN_START
****
Q: Sentence 1:Following suit , Li Chongxun first killed his siblings , but as he prepared to kill his wife , she hid under the curtains of her bedroom . Sentence 2:nan

A: SINGLE_S_COORD_ANAPHORA
****
Q: Sentence 1:Professor Amamori discovers a 10th planet in the Earth 's solar system , which he names La - Metal , while at his observatory in Tokyo . Sentence 2:nan

A:
SINGLE_RELATIVE
****