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:       What's the Mountaineering Club doing this weekend ?  
 Person2:We are going to climb a cliff on the Yangtze River .  
 Person1:        How hard is the climb ?  
 Person2:It is a very difficult climb , because there are not many places to put your hands and feet .  
 Person1:        What did you do last week ?  
 Person2:We rappelled down the side of a 300 - foot cliff . It's very exciting .  
 Person1:        Wow . That sounds like a lot of fun . I am sorry I missed it .  
 Person2:Well , you should come this weekend . I think you could do the climb .  
 Person1:        Yeah , I will . See you then !  
 Person2:Ok , see you . 

informal