1 mole of ideal gas with internal energy $U(T) = \frac{3}{2}RT$ , expands from initial volume $V_i = \frac{1}{10} V_0$ following the relation $$p = − \frac{p_0}{V_0}V + p_0$$ The highest temperature during the process can be written as $\frac{a}{b}T_0$, where a and b are coprime. What is the value of $a-b$?