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:       Oh , Mary , come in , please . I'm so happy to see you .  
 Person2:Happy birthday , George . Many happy returns of the day . Here's a present for you .  
 Person1:        Oh , thank you , Mary . You're so nice .  
 Person2:I hope you like it . Oh , have the other guys arrived ?  
 Person1:        They're all waiting for you . Let's join them . I'm going to cut the cake soon .  
 Person2:Let's go . 

informal