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: 'Did you bring any water to start?' 'Yes! Did you bring any food to start?' 'I did, but my friend only feels comfortable with extra around, God forbid, if something happens this could save his life. So I'm thinking, I take all three food packages, two firewood packages and leave all three water and one firewood for you. '
Utterance: 'I think that it is fair that you get three food and I get three water, but why should you get two firewood to my one?'

Yes