Determinant of upper triangular matrix

Algebra Level 2

Find the determinant of the matrix

\[\left(\begin{array}{cc}1&0&-1&9&11\\0&-6&-1&9&11\\0&0&\frac{1}{3}&-80&\frac{1}{3}\\0&0&0&9&7\\0&0&0&0&-5 \end{array}\right).\]