Voting rules: Choose the paper you think is the most difficult!
This is a community-based ranking of the most difficult paper in the world. We do our best to provide fair voting, but it is not intended to be exhaustive. So if you notice something or Sheet is missing, feel free to help improve the ranking!
A participant may cast an up or down vote for each Sheet once every 24 hours. The rank of each Sheet is then calculated from the weighted sum of all up and down votes.