So one H ion comes from here, the other H ion comes from here. And the two electrons are found on the NADH. And we ultimately oxidize the NADH into NAD plus and we form the SMN H two. And this takes place on the matrix side of this complex one. So once again, the NADH molecule donates the two electrons onto an acceptor group found on the vertical component of complex one known as flavin mononucleotide fmmen. The FMN is reduced into FMM H two.