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:       There was something wrong with the plane last Thursday .  
 Person2:Which flight ?  
 Person1:        Flight 198 . Fortunately , there were few passengers .  
 Person2:How about the passengers ?  
 Person1:        Well , all the passengers and crew members landed on their feet finally . 

formal