Singular value decomposition

Compute the singular values of the following matrix:$$A=\left( \begin{array}{cccc} 1 & 1 & 1 & 1 \\ 2 & 2 & -2 & -2 \\ 3 & -3 & 3 & -3 \\ \end{array} \right)$$Write them in descending order separated by a space.