RC2: a python-based maxsat solver. An implementation of the RC2 algorithm for solving maximum satisfiability. RC2 stands for relaxable cardinality constraints (alternatively, soft cardinality constraints) and represents an improved version of the OLLITI algorithm, which was described in 1 and 2 and originally implemented in the MSCG MaxSAT solver. Initially, this solver was supposed to serve as an example of a possible PySAT usage illustrating how a state-of-the-art MaxSAT algorithm could be implemented in Python and still be efficient. It participated in the MaxSAT Evaluations 2018 and 2019 where, surprisingly, it was ranked first in two complete categories: unweighted and weighted. A brief solver description can be found in 3. A more detailed solver description can be found in 4