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:       Fairly warm this morning , isn't it ?  
 Person2:You're right.The air is so warm and everything looks so fresh and green .  
 Person1:        Say , how about a walk along the river ?  
 Person2:Marvelous idea ? 

informal