CF243D Cubes

One day Petya got a set of wooden cubes as a present from his mom. Petya immediately built a whole city from these cubes. The base of the city is an $ n×n $ square, divided into unit squares. The square's sides are parallel to the coordinate axes, the square's opposite corners have coordinates $ (0,0) $ and $ (n,n) $ . On each of the unit squares Petya built a tower of wooden cubes. The side of a wooden cube also has a unit length. After that Petya went an infinitely large distance away from his masterpiece and looked at it in the direction of vector $ v=(v_{x},v_{y},0) $ . Petya wonders, how many distinct cubes are visible from this position. Help him, find this number. Each cube includes the border. We think that a cube is visible if there is a ray emanating from some point $ p $ , belonging to the cube, in the direction of vector $ -v $ , that doesn't contain any points, belonging to other cubes.

The first line contains three integers $ n $ , $ v_{x} $ and $ v_{y} $ ( $ 1

Print a single integer — the number of visible cubes. Please, do not use the %lld specifier to read or write 64-bit integers in С++. It is preferred to use the cin, cout streams or the %I64d specifier.