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:       What's this , I wonder ?  
 Person2:I'm not sure.Let me have a look ... It could be a coffee grinder .  
 Person1:        A coffee grinder ?  
 Person2:Yes , it must be used for grinding coffee beans .  
 Person1:        Oh , that would be very useful . 

informal