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'.

Sentence 1:An eager vigilante is causing a stir in the city , while Krang and Shredder take control of all the machines in the city . Sentence 2:nan
SINGLE_CONN_INNER

Sentence 1:Ross was widely known as a lecturer and institute instructor . Sentence 2:He was president of Capitol College in Columbus which was renamed Dominion University when it relocated to Westerville Ohio .
PAIR_ANAPHORA

Sentence 1:We studied the psychrophilic lichen Pleopsidium chlorophanum , because it lives in Earth 's most Mars - like environmental conditions . Sentence 2:nan

SINGLE_CONN_INNER