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:       Welcome to my birthday party , I am so happy you can come .  
 Person2:Thanks for inviting me . Here is the gift for you . Happy birthday , Francis ! Many more happy and healthy years for you !  
 Person1:        Thank you , shall I open it now ?  
 Person2:Yes , please do .  
 Person1:        Wow , a remote car model and my favorite brand . I really like it . That is so nice of you .  
 Person2:Yeah , I was really struggling whether I should give you this nice little car . It was the last one they had and I really like it so much myself .  
 Person1:        Typical you , always wanting to keep the best things for yourself . The more I appreciate the gift now . 

informal