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:       Thanks for inviting me over for dinner this evening .  
 Person2:You're welcome .  
 Person1:        It looks delicious .  
 Person2:Well here . Help yourself to some shrimp . It's fresh . 

informal