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 he never flew into space , he served as a backup crew member on the Soyuz 16 , Soyuz 32 , Soyuz 35 , and Soyuz T - 4 missions . Sentence 2:nan

A: SINGLE_CONN_START
****
Q: Sentence 1:Milan then fell under the lordship of Sforza , whom Colleoni served for a time , but in 1448 he took leave of Sforza and returned to the Venetians . Sentence 2:nan

A: SINGLE_RELATIVE
****
Q: Sentence 1:However , because Kanako found out Mariya 's secret before she began attending the school , it was null , and because Kanako knew Shizu 's true gender . Sentence 2:nan

A:
SINGLE_CONN_INNER
****