Electrochemistry

For the following cell with hydrogen electrodes at two different pressure p₁ and p₂. What will be the emf for the given cell : \eqalign{ & Pt({H_2})|{H^ + }(aq)|Pt({H_2}) \cr & \,\,\,\,\,{p_1}\,\,\,\,\,\,\,\,\,\,\,\,\,\,1M\,\,\,\,\,\,\,\,\,\,\,\,{p_2} \cr}