Detailed Instructions: 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'.
Problem: Person1: Mr . Wilson . I'm very glad we reached the agreement at last . Now I'd like to propose a toast to the further development of our cooperation .
Person2:I'm very delighted too . I'm sure that we'll have a wider range of cooperation . So , let's drink to the signing of our contract .
Person1: Bottoms up !
Person2:Cheers .
Solution:
informal