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 elicit-pref strategy, otherwise output No. elicit-pref is a cooperative negotiation strategy. It is used to discover the preference order of the opponent in the negotiation.

Ex Input:
Context: 'I agree! Nice to meet you... I have two boys who always eat! Any chance I canget 2 food?' 'Food is the item of greatest value to you?' 'It is! What do you think?'
Utterance: 'The item of greatest value to me is WATER. Before thinking about an offer I need to know what your priorities are and you need to know mine in order to conclude something fair for both of you.'

Ex Output:
Yes


Ex Input:
Context: 'I would be interested in firewood.  Can I ask you, what are your primary concerns on this trip?' 'My primary concerns are staying hydrated, I have been feeling sick and throwing up from being so high up in the mountains. ' 'Oh, so sorry to hear that.  I can understand why water would be important to you.  I am worried about being too cold at night. My sleeping bag is not rated well for cold weather (I packed the wring one).'
Utterance: 'Oh I understand that for sure. I am not used to the cold weather either which is not helping. Would you be interested in a trade for water in exchange for firewood? '

Ex Output:
No


Ex Input:
Context: 'Good afternoon. Ok, water is a medium need for me. I have some to get by. I really need firewood. It's cold.' 'I'd be willing to give up all the firewood in exchange for the water. I also am low on Food and would need at least 2.' 'That doesn't sound like something I can agree to. Do you have any other ideas?'
Utterance: 'I can keep 2 of the firewood then and offer you 2 of the food. I'd take the water, 2 firewood and 1 water'

Ex Output:

No