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: Consider Input: Person1: I am not convinced by your explanation . Could you explain it ?
Person2:Sorry , I really can't do that . There's little time left for us .
Person1: I can't accept your excuse . It's five o'clock .
Person2:Yeah . But I have an appointment with Ann .
Person1: Ok , sounds good . But I think it's your trick .

Output: informal

Input: Consider Input: Person1: Hi , I want to see the Terra Cotta Warriors in Xi'an . Could you please remind me when we are arriving at that stop ?
Person2:Oh . You took the wrong bus . You need to take Bus 151 which goes the opposite direction .
Person1: Oh , no ! What should I do now ?
Person2:Don't worry . You can get off at the next stop and walk across the street and take the Bus 151 to the opposite direction .
Person1: Ok . How many stops do I have to go ?
Person2:About 15 stops .
Person1: That is a long way to go . It is so kind of you to help me . Thank you very much .
Person2:My pleasure .

Output: informal

Input: Consider Input: Person1: What's the temperature today ?
Person2:It's about 5 degrees centigrade .
Person1: What's the weather forecast for tomorrow ?
Person2:The weatherman says it's going to snow tomorrow .
Person1: Are you used to the climate here ?
Person2:I think I'll soon get used to it .
Person1: What is the average temperature of Beijing ?
Person2:lt's about 180C , but in winter the temperature may fall to 10-15 degrees below zero . And we have a long winter .
Person1: Which season do you like best ?
Person2:I prefer spring when little by little everything becomes green and the weather is almost always nice .
Output: formal