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:       Repairman.May I come in ? 
 Person2:Come in please . 
 Person1:        What's the matter , sir ? 
 Person2:The toilet doesn't flush . 
 Person1:        Let me see.En .. it's right now.You can try it . 
 Person2:Wonderfull.Thanks a lot . 
 Person1:        You are welcome . 

informal