Definition: The input is taken from a negotiation between two participants who take the role of campsite neighbors and negotiate for Food, Water, and Firewood packages, based on their individual preferences and requirements. Given an utterance and recent dialogue context containing past 3 utterances (wherever available), output Yes if the utterance contains the vouch-fair strategy, otherwise output No. vouch-fair is a selfish negotiation strategy. It is used to call out fairness for personal benefit, either when acknowledging a fair deal or when the opponent offers a deal that benefits them. This can be through an explicit call out or can be implied.
Input: Context: 'I would also like a little extra food for my kids. Maybe we can split it somehow?' 'Ok, I am willing to give you one food, in exchange for two firewoods, that would mean you get 3 waters, 1 food and 1 firewood. you get 5 items, while i get 4.' 'If I only get 1 food, than I would like 2 firewood. So you get 2 food, 1 firewood, and 1 water.'
Utterance: 'No i do not need water, as i am camping near a potable stream. I would like 2 firewood. It is only fair that i get two firewood, since you are getting more supplies (5), i think i should be able to choose what 4 i should get.'

Yes