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'.

Input: Consider Input: Sentence 1:Describing these elements as functions of design , he argues the urban designer should be aware of these elements and use them as tools when developing a ' design idea ' of what the city or place ought to look like . Sentence 2:nan

Output: SINGLE_CATAPHORA


Input: Consider Input: Sentence 1:A space charge develops a potential that slows the carriers down . Sentence 2:For example , an electron approaching a cloud of other electrons will slow down due to the repulsive force .

Output: PAIR_CONN


Input: Consider Input: Sentence 1:The contract was expected to be completed in four years , but the headings met on 20 April 1954 with the concrete lining finished a month later . Sentence 2:nan


Output: SINGLE_S_COORD