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:       Great party , isn ’ t it ?  
 Person2:Yeah , really .  
 Person1:        By the way , my name is Liu Wei .  
 Person2:Hi , I ’ m Susan Marshall.You can call me Susan.Nice to meet you .  
 Person1:        What do you do , Susan ?  
 Person2:Well , I ’ m a college student.How about you ?  
 Person1:        I work for the Bank of China , in the International Section .  
 Person2:I work for the Bank of China , in the International Section . 

formal