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[References: 72 tit.]

The mass of the top quark is measured using a sample of tt¯tt¯ events collected by the CMS detector using proton-proton collisions at s√=13s=13 TeVTeV at the CERN LHC. Events are selected with one isolated muon or electron and at least four jets from data corresponding to an integrated luminosity of 35.9fb−1fb−1. For each event the mass is reconstructed from a kinematic fit of the decay products to a tt¯tt¯ hypothesis. Using the ideogram method, the top quark mass is determined simultaneously with an overall jet energy scale factor (JSF), constrained by the mass of the W boson in qq¯¯¯′qq¯′ decays. The measurement is calibrated on samples simulated at next-to-leading order matched to a leading-order parton shower. The top quark mass is found to be 172.25±0.08(stat+JSF)±0.62(syst)GeV172.25±0.08(stat+JSF)±0.62(syst)GeV. The dependence of this result on the kinematic properties of the event is studied and compared to predictions of different models of tt¯tt¯ production, and no indications of a bias in the measurements are observed.