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:       Can you help me ? This fitting has come loose and I need something to tighten it up .  
 Person2:Let's have a look . Oh yes , you need a 10 mm ring spanner . Here you are . Just leave it on the workbench when you finish .  
 Person1:        Thanks for your help .  
 Person2:No problem . 

informal