[Shirro]

I have a following problem:

In unaerobic enviroment, there is Manganese dioxide and hydrogen sulfide.
[Mn²⁺]=10^-3 M
[SO₄^2-]=10^-5 M
[H₂S]=10^2-
SO₄^2- + 10 H⁺ + 2 e^-  <-> H₂S + 4 H₂O     E_H⁰ = + 0,31 V
MnO₂(s) + 4 H⁺ + 2 e^- <-> Mn²⁺ + 2 H₂O         E_H⁰= + 1,29 V

I'm asked to do pe vs. pH diagram. Can anyone tell me  how to do this?