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:       Hi , Monica , congratulations ! Your presentation at the meeting was very successful and everyone was impressed by your speech . And it was so persuasive and I bet our clients will be convinced to invest their money in this project . You really made a big contribution to our company .  
 Person2:Thank you , I just tried my best . I am very happy to know you like it .  
 Person1:        You must have been prepared for a long time . Some statistics in this presentation are not easy to find , right ?  
 Person2:Well , yes . Several colleagues from different departments helped me with that . They are very supportive . I consulted an economic expert last week . He was very kind to give valuable suggestions .  
 Person1:        Now , the effort pays off . You have accomplished something .  
 Person2:Come on , don ’ t flatter me anymore . I took the job because I love being challenged . But I can ’ t get this turned around without the support from you people . 

informal