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:       I love that vase .  
 Person2:Do you really like it ?  
 Person1:        Yes , it looks perfect .  
 Person2:It wasn't very expensive either .  
 Person1:        That's amazing ! 

informal