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:It has become an ongoing tradition that the Pelican editor appears naked on the front cover of the final edition , although it is unknown when this tradition began . Sentence 2:nan

A: SINGLE_CONN_INNER
****
Q: Sentence 1:Although Bernstein left as music director in 1969 , he continued to lead the Young People 's Concerts as Conductor Emeritus until 1972 . Sentence 2:nan

A: SINGLE_CONN_START
****
Q: Sentence 1:Flying his Albatros D.Va marked with blue and white diamonds , he scored a victory for his new squadron on 9 December 1917 , to run his total to seven . Sentence 2:nan

A:
SINGLE_CATAPHORA
****