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'.

[EX Q]: Sentence 1:The fluid pumping efficiency of a valveless system , however , is not necessarily lower than that having valves . Sentence 2:In fact , many fluid - dynamical systems in nature and engineering more or less rely upon valveless pumping to transport the working fluids therein .
[EX A]: PAIR_CONN

[EX Q]: Sentence 1:The Greek captain , Apostolos Mangouras , reported a loud bang from the starboard side and as the ship began to take on water from high waves the engines shut down and he called for help from Spanish rescue workers . Sentence 2:nan
[EX A]: SINGLE_S_COORD_ANAPHORA

[EX Q]: Sentence 1:Feeling deeply disappointed , Gilbert distances himself from Anne . Sentence 2:nan
[EX A]:
SINGLE_CATAPHORA