Singular Values & the SVD · Easy problem

A $2\times 2$ matrix is given by its SVD pieces: $A = 5\,u_1v_1^{T} + 2\,u_2v_2^{T}$ with $u_1 = \begin{pmatrix}3/5\\4/5\end{pmatrix}$, $u_2 = \begin{pmatrix}-4/5\\3/5\end{pmatrix}$, $v_1 = \begin{pmatrix}1\\0\end{pmatrix}$, $v_2 = \begin{pmatrix}0\\1\end{pmatrix}$. Find the entry $a_{21}$ (row 2, column 1).