Na igualdade matricial $\left[\begin{array}{ccc}1& 0& 0\\ x& 1& 0\\ y& x& 1\end{array}\right]\cdot \left[\begin{array}{c}1\\ 2\\ 3\end{array}\right]=\left[\begin{array}{c}1\\ 1\\ 1\end{array}\right]$, o valor de $x+y$ é