We present a lattice QCD determination of the average up-down, strange and
charm quark masses based on simulations performed by the European Twisted Mass
Collaboration with Nfā=2+1+1 dynamical fermions. We simulated at three
different values of the lattice spacing, the smallest being approximately
0.06fm, and with pion masses as small as 210MeV. Our results are:
mudā(2GeV)=3.70(17)MeV,
msā(2GeV)=99.2(3.9)MeV, mcā(mcā)=1.350(49)GeV,
msā/mudā=26.64(30) and mcā/msā=11.65(12)