Recovering the distribution grid topology in real time is essential to perform several distribution system operator (DSO) functions. DSOs often do not have any direct monitoring of switch statuses to track reconfiguration. At the same time, installing real-time meters at a large number of buses is challenging due to the cost of endowing every metered bus with a real-time communication channel. The goal of this letter is to develop a meter placement strategy allowing DSOs to deploy only few real-time meters. After casting the topology recovery task as an optimization problem, a meter placement strategy ensuring unique recovery of the true topology is devised. A graph-theoretical approach is pursued to partition the grid into connected portions called observable islands. The proposed strategy then simply requires installing a meter in the path between every pair of boundary nodes, i.e., ends of edges connecting two different islands. Under some ideal assumptions, this placement strategy ensures unique recovery of the topology. The approach is also validated through numerical simulations under realistic scenarios using a standard IEEE benchmark feeder.