5. The number of integer points within the square (including the four sides) formed by the four lines $y=x+10, y=-x+10, y=$ $x-10, y=-x-10$ in the Cartesian coordinate system is $\qquad$ .
(Tip: By plotting, it is known that the number of integer points in each quadrant is 45. The number of integer points on the coordinate axes is 41, so, the number of integer points is $(4 \times 45+41=) 221$.