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 really late but I'm starving .  
 Person2:Hey , that coffee shop's lights are still on .  
 Person1:        Maybe they have some good pie .  
 Person2:I would love a really sticky cinnamon bun .  
 Person1:        There was a coffee shop by my house when I was a kid that served cinnamon hot chocolate .  
 Person2:Mmmm . That sounds like something I had in Mexico once .  
 Person1:        Good stuff ... Oh , no . The door is locked .  
 Person2:Ohhhhh ! And I just got all my juices going ! 

informal