Sejam as matrizes $A^t=\left[\begin{array}{cc}2& 4\\ x+1& 3\end{array}\right]$ e $B^t=\left[\begin{array}{cc}1& 2y-3\\ -3& 1\end{array}\right]$. Se $A+B=\left[\begin{array}{cc}3& 2\\ 5& 4\end{array}\right]$, então $x+y$ é