Let $A$ be a matrix with distinct eigenvalues $\lambda_1 = 3$ and $\lambda_2 = 5$. Let $x_1$ be a right eigenvector of $A$ for $\lambda_1$, and let $y_2$ be a left eigenvector of $A$ for $\lambda_2$ (so $y_2^H A = 5 y_2^H$). What is the value of the inner product $\langle x_1, y_2 \rangle = y_2^H x_1$?