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:       Hello 。 this is Susan .  
 Person2:Hello , I ’ m Mark . I ’ m just wondering if you are free this weekend .  
 Person1:        Yes , I think So .  
 Person2:Good . I was thinking that I ’ d like to invite you to watch a movie . I can meet you at the cinema gate .  
 Person1:        What ’ s the time ?  
 Person2:Six thirty , tonight .  
 Person1:        Oh , I ’ m sorry I can ’ t.because I have to do some housework.You can ask Jenny to go with you .  
 Person2:All right.Maybe next time I can go with you.Bye !  
 Person1:        Good bye ! 

formal