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:       Mike promised to help us . 
 Person2:Mike ? How can you trust him to help us ? 
 Person1:        Why not ? 
 Person2:He is too unpredictable . He says anything that pops into his head . And then he forgets it all . 

formal