Chef and new weapon

There are $N$ targets placed in a field, the plane of the field is cartesian. Each target is associated with coordinates $(x, y)$. Chef has placed his new weapon at the point $(x_0, y_0)$. In one shot it can destroy all the targets on some line that crosses point $(x_0, y_0)$. Determine the number of shots required to destroy all targets. ###Input - The first line contains $N$ the number of targe