Using half-reactions to design a galvanic cell

Question

Assignment:

Use the following pair of half-reactions to design a galvanic cell. Then write in the proper coefficient for each of the species involved in the overall reaction. Water molecules and protons are not shown in the half-reactions, but they may be needed to the overall reaction.

N₂(g)->N₂H₅⁺(aq) E=-.023V
MnO₄^-(aq) -> Mn²⁺ (aq) E=1.51V

Coefficients of MnO4-(aq), N2(g), Mn2+ (aq), N2H5+ (aq), H+(aq), and H2O(l)?

What is the standard potential of this voltaic cell in volts (V)?