Definition: You are given a conversation between two people. 'Person1:' and 'Person2:' are used to separate their respective dialogues. You are required to assign a label 'formal' if there is an absence of emotion and a presence of questions anywhere within the conversation. If such pattern is not found assign the label 'informal'.
Input:  Person1:       It's terrible how things have changed.You remember there used to be trees on all these hills . 
 Person2:Really ? There aren't many left now . 
 Person1:        No , they've all been cut down and now all the soil is washing away . 
 Person2:Were there any animals in the forest ? 
 Person1:        Yes , I can remember it very well that there used to be all sorts of animals and birds.But nowadays you just don't see the birds that you used to see around here . 

informal