A set of objects, some goods and some bads, is to be divided fairly among agents with different tastes, modeled by additive utility-functions. If the objects cannot be shared, so that each of them must be entirely allocated to a single agent, then fair division may not exist. What is the smallest number of objects that must be shared between two or more agents in order to attain a fair division?We focus on Pareto-optimal, envy-free and/or proportional allocations. We show that, for a generic instance of the problem -all instances except of a zero-measure set of degenerate problems -a fair and Pareto-optimal division with the smallest possible number of shared objects can be found in polynomial time, assuming that the number of agents is fixed. The problem becomes computationally hard for degenerate instances, where the agents' valuations are aligned for many objects. * This work was inspired by Achikam Bitan, Steven Brams and Shahar Dobzinski, who expressed their dissatisfaction with the current trend of approximate-fairness (SCADA conference, Weizmann Institute, Israel 2018). We are grateful to participants of De Aequa Divisione Workshop on Fair Division (LUISS, Rome, 2019) and the Workshop on Theoretical Aspects of Fairness (WTAF, Patras, 2019) for their comments. Suggestions of Herve Moulin, Antonio Nicolo, and Nisarg Shah were especially useful. Several members of the theoretical-computer-science stackexchange network (http://cstheory.stackexchange.com) provided very helpful answers, in particular: D.