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:       Smith is always careless , it is his Achilles ’ s heel .  
 Person2:He would get very angry if anyone criticized him .  
 Person1:        He will burn his fingers .  
 Person2:If only he knew it . 

informal