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: 'Me too. We invited a lot of extra friends' 'I am hoping we have enough food. I'm worried we might run out so I'd like to get some more ' 'I know we need extra food too and some firewood. Maybe a little water but we shouldn't need too much'
Utterance: 'It sounds like we are looking for the same things. I think there are some extra we can share. Do you have an idea about how it can be the most fair? '

Yes