B"Last year the world's largest square was built in Berland. It is known that the square can be represented as an infinite plane with an introduced Cartesian system of coordinates. On that square two sets of concentric circles were painted. Let's call the set of concentric circles with radii 1, xe2 x80 x892, xe2 x80 x89..., xe2 x80 x89K and the center in the point (z, xe2 x80 x890) a (K, xe2 x80 x89z)-set. Thus, on the square were painted a (N, xe2 x80 x89x)-set and a (M, xe2 x80 x89y)-set. You have to find out how many parts those sets divided the square into. The first line contains integers N, xe2 x80 x89x, xe2 x80 x89M, xe2 x80 x89y. (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89N, xe2 x80 x89M xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89100000, xe2 x80 x89 xe2 x80 x89- xe2 x80 x89100000 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89x, xe2 x80 x89y xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89100000, xe2 x80 x89x xe2 x80 x89 xe2 x89 xa0 xe2 x80 x89y). Print the sought number of parts. Picture for the third sample:"...