  Quantum contextuality is one of the most recognized resources in quantum
communication and computing scenarios. We provide a new quantifier of this
resource, the rank of contextuality (RC). We define RC as the minimum number of
non-contextual behaviors that are needed to simulate a contextual behavior. We
show that the logarithm of RC is a natural contextuality measure satisfying
several properties considered in the spirit of the resource-theoretic approach.
The properties include faithfulness, monotonicity, and additivity under tensor
product. We also give examples of how to construct contextual behaviors with an
arbitrary value of RC exhibiting a natural connection between this quantifier
and the arboricity of an underlying hypergraph. We also discuss exemplary areas
of research in which the new measure appears as a natural quantifier.
