Parallel voting describes a mixed voting system where voters in effect participate in two separate elections for a single chamber using different systems, and where the results in one election have little or no impact on the results of the other. Specifically, it usually refers to the semi-proportional system used in Japan, South Korea, Taiwan, some regions of Russia and elsewhere, sometimes known as the Supplementary Member (SM) system or, by some political scientists, Mixed Member Majoritarian (MMM), which combines first-past-the-post voting (FPTP) with party-list proportional representation. Parallel voting or MMM is distinct from mixed member proportional representation (MMP) where a single election takes place, and the party vote determines what share of seats each party will receive in the legislature to "top up" its constituency seats.