G4.4 If $x_{1}, x_{2}, x_{3}, x_{4}$ and $x_{5}$ are positive integers that satisfy $x_{1}+x_{2}+x_{3}+x_{4}+x_{5}=x_{1} x_{2} x_{3} x_{4} x_{5}$, that is the sum is the product, find the maximum value of $x_{5}$.