Electrochemistry

If molar conductance at infinite dilution for $\text{CH}_3\text{COO}^-$ and $\text{H}^+$ ions are $50\ \text{S cm}^2\ \text{mol}^{-1}$ and $350\ \text{S cm}^2\ \text{mol}^{-1}$ respectively, molar conductivity of $5 \times 10^{-2}$ M $\text{CH}_3\text{COOH}$ is $20\ \text{S cm}^2\text{mol}^{-1}$. What is the hydrogen ion concentration in $\text{mol/dm}^3$ of $\text{CH}_3\text{COOH}$?