Let $P$ and $Q$ are two sets such that
\[
n(P)=27,\quad n(Q)=17,\quad n(P\cap Q)=5.
\]
If $x$ is the number of ways of selecting $7$ elements from $P$ such that all the elements of $P\cap Q$ are in each selection and $y$ is the number of ways of selecting $10$ elements from $Q$ such that no element of $P\cap Q$ is present in any selection, then $x+y+1=$