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:       Hey ! Ask your mom for more old pictures , OK ?  
 Person2:Can't it wait ? She's still angry that we sent e-mail wedding invitations .  
 Person1:        But we saved your parents so much money ...  
 Person2:I know . And they're spending enough on the plane tickets to Texas !  
 Person1:        Speaking of plane tickets , don't forget to check on the reservations !  
 Person2:OK . 

informal