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:       Mumm . Those burgers smell great . It's perfect day for a barbecue .  
 Person2:It sure is . I'm glad it didn't rain . My name's Mike Gates , by the way .  
 Person1:        Oh , hi ! I'm Barbara Johnson . Nice to meet you .  
 Person2:I'm sorry . What's your name again ?  
 Person1:        Barbara . But please , just call me Barb .  
 Person2:So Barb ... what do you do ?  
 Person1:        I'm studying medicine .  
 Person2:Really ? Where ?  
 Person1:        At Harvard . What about you ?  
 Person2:I'm an engineer at IBM .  
 Person1:        Oh , are you ? That sounds interesting .  
 Person2:Yeah . I like it . Hey , it looks like the food is ready .  
 Person1:        Good . I'm starving . 

informal