<image>As shown in the figure, in the plane rectangular coordinate system, there are several points with integer x-coordinates arranged in the direction indicated by the “$$→$$” in the figure, such as $$(1,0)$$, $$(2,0)$$, $$(2,1)$$, $$(1,1)$$, $$(1,2)$$, $$(2,2)$$, etc. The x-coordinate of the 81st point is ______ .