Santa Claus has Robot which lives on the infinite grid and can movealong its lines. He can also, having a sequence of $m$ points $p_1,p_2,...,p_m$ with integer coordinates, do the following: denote its initial location by $p_0$. First, the robot will move from $p_0$ to $p_1$ along one of the shortest paths between them (please notice that since the robot moves only along the grid lines, there can be several shortest paths). Then, after it reaches $p_1$, it'll move to $p_2$, again, choosing one of the shortest ways, then to $p_3$, and so on, until he has visited all points in the given order. Some of the points in the sequence may coincide, in that case Robot will visit that point several times according to the sequence order.