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.
Q: Context: 'If I do that, I will need all the food, since I won't be able to cook much fish.' 'I see. I do need at least 1 food package because I will be spending lots of calories working. But I can give you all the water.' 'How about this, you get one firewood and one food, and I get all the water?'
Utterance: 'No, sorry. How about you get one firewood, two food and all the water?'
A: 
Yes