Let $\alpha, \beta$ be non-zero real numbers and $v_1, v_2$ be two non-zero vectors of size $3 \times 1$. Suppose $v_1^T v_2 = 0$, $v_1^T v_1 = 1$, $v_2^T v_2 = 1$. Let
\[
A = \alpha v_1 v_1^T + \beta v_2 v_2^T.
\]
The eigenvalues of $A$ are ____________.
