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:       Have you heard about Alice and David ?  
 Person2:No , have they had another fight ?  
 Person1:        No , they've got engaged .  
 Person2:You must be joking . Those two ?  
 Person1:        Well , my dear , I didn't believe it either . But I got it straight from the horse's mouth . David called me this morning .  
 Person2:So when did this all happen ?  
 Person1:        Last weekend , while they were on their ski trip .  
 Person2:Well , I believe it now , and when are they are getting married ?  
 Person1:        Next June .  
 Person2:I can hardly believe it . 

informal