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 Input:
Sentence 1:For large numbers , the Poisson distribution approaches a normal distribution about its mean , and the elementary events ( photons , electrons , etc . ) are no longer individually observed , typically making shot noise in actual observations indistinguishable from true Gaussian noise . Sentence 2:nan

Ex Output:
SINGLE_S_COORD

Ex Input:
Sentence 1:Thus the Cnossians , in short time , not only lost most of their allies , but also their hegemony over the island . Sentence 2:Nevertheless they were still able to assist the Aetolian allies with 1000 archers in their war on the continent .

Ex Output:
PAIR_CONN_ANAPHORA

Ex Input:
Sentence 1:Jacob studied for a Bachelor of Science in physics at American College , Madurai from 1992 to 1995 . Sentence 2:Later , inspired by his mother 's cooking , he went on to study catering .

Ex Output:
PAIR_ANAPHORA