Two days.
In two days the summit would officially conclude.
According to Adrien, if the parties couldn't come to an agreement of any kind it was possible for it to drag on.
However, due to the fact that King Gregor himself was involved in the negotiations - not to mention Prince Adrien and the leaders of several other small nations who could not spare delegates - it would be frowned upon.
Reasonably, there would be great pressure to come to some agreement or another by the end of the two days rather than drag it on.
As things stood, they were the moving party, and so 'any kind of agreement' would likely be good for them.
Honestly...though...
The sooner the summit was over, the better. If she had the power to just agree to anything just to make it end...she'd be sorely tempted to, no matter what the terms might be. It was probably for the best, then, that she didn't get to decide.