If $A=\varphi ,P\left(A\right)$ denotes power set of $A$, then number of elements in $P\left(P\left(P\left(P\left(P\left(A\right)\right)\right)\right)\right)$ is

$A=\left\{\left(x,y\right):x,y\in I,x\ge 0,y\ge 0 \mathrm{and} 4x+5y\le 40\} \right\}$

$B=\left\{\left(x,y\right):x,y\in I,x\ge 0,y\ge 0 \mathrm{and} 5x+4y\le 40\right\}$

where $I$ denotes set of integers, then $n\left(A\cap B\right)=$