If A=\left|\begin{array}{ccc}1 & 0 & 0 \ x & 1 & 0 \ x & x & 1|\end{array} and I=\left|\begin{array}{ccc}1 & 0 & 0 \ 0 & 1 & 0 \ 0 & 0 & 1|\end{array} then A^3-3 A^2+3 A+I is equal to