The molar conductivity at infinite dilution of barium chloride, sulphuric arid and hydrochloric acid are $280, 860$ $426 {\mathrm{Scm}}^2{\mathrm{mol}}^{-1}$ respectively. The molar conductivity at infinite dilution of barium sulphate is ___ ${\mathrm{Scm}}^2{ \mathrm{mol}}^{-1}$ ( Round off to the Nearest Integer).