An organic compound P with molecular formula C9H18O2 decolorizes bromine water and also shows positive iodoform test. P on ozonolysis followed by treatment with H2O2 gives Q and R. While compound Q shows positive iodoform test, compound R does not give positive iodoform test. Q and R on oxidation with pyridinium chlorochromate (PCC) followed by heating give S and T, respectively. Both S and T show positive iodoform test. Complete copolymerization of 500 moles of Q and 500 moles of R gives one mole of a single acyclic copolymer U. [Given, atomic mass: H =1, C = 12, O =16] Sum of number of oxygen atoms in S and T is _____