Gopher II

The gopher family, having averted the canine threat, must face a new predator. The are n gophers and m gopher holes, each at distinct (x,y) coordinates. A hawk arrives and if a gopher does not reach a hole in s seconds it is vul- nerable to being eaten. A hole can save at most one gopher. All the gophers run at the same velocity v. The gopher family needs an escape strategy that min- imizes the number of vulnerable gophers. Input The input contains several cases. The first line of each case contains four positive integers less than 100: n, m, s, and v. The next n lines give the coordinates of the gophers; the following m lines give the coordinates of the gopher holes. All distances are in metres; all times are in seconds; all velocities are in metres per second. Output Output consists of a single line for each case, giving the number of vulnerable gophers. Sample Input 2 2 5 10 1.0 1.0 2.0 2.0 100.0 100.0 20.0 20.0 Sample Output 1