The very rare Formula omitted decay is searched for by analysing Formula omitted decays. The analysis uses a sample of beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 Formula omitted. The signal signature corresponds to simultaneous peaks in the Formula omitted and Formula omitted invariant masses. No evidence for an excess of events over background is observed and an upper limit is set on the branching fraction of the decay at Formula omitted at Formula omitted confidence level. This is the first limit on the branching fraction of Formula omitted decays and the most stringent limit on Formula omitted decays to leptonic final states. The analysis is the first search for a rare charm-meson decay exploiting production via beauty decays.