B'One day Vasya painted a Cartesian coordinate system on a piece of paper and marked some set of points (x1, xe2 x80 x89y1), xe2 x80 x89(x2, xe2 x80 x89y2), xe2 x80 x89..., xe2 x80 x89(xn, xe2 x80 x89yn). Let 's define neighbors for some fixed point from the given set (x, xe2 x80 x89y): We 'll consider point (x, xe2 x80 x89y) from the given set supercentral, if it has at least one upper, at least one lower, at least one left and at least one right neighbor among this set 's points. Vasya marked quite many points on the paper. Analyzing the picture manually is rather a challenge, so Vasya asked you to help him. Your task is to find the number of supercentral points in the given set. The first input line contains the only integer n (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89200) -- the number of points in the given set. Next n lines contain the coordinates of the points written as "x y" (without the quotes) (|x|, xe2 x80 x89|y| xe2 x80 x89 xe2 x89 xa4 xe2 x80 x891000), all coordinates are integers. The numbers in the line are separated by exactly one space. It is guaranteed that all points are different. Print the only number -- the number of supercentral points of the given set. In the first sample the supercentral points are only points (1, xe2 x80 x891) and (1, xe2 x80 x892). In the second sample there is one supercental point -- point (0, xe2 x80 x890).'...