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:       How'd you like to go on a bungee jump this weekend ?  
 Person2:I'm not sure . I promised to help my sister move Saturday .  
 Person1:        How about Sunday , then ? We could start in the morning .  
 Person2:I might be able to do that . But I don't think I can do it well .  
 Person1:        Don't worry . It is a test of physical endurance , intelligence . Just to finish it is considered a victory for most .  
 Person2:OK . I'll talk to you later . 

informal