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
vulnerable 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 minimizes 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 coordinates
are decimal numbers between 0 and 100 with one digit after the
decimal point. 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 1 
Sample Output 1 
2 2 5 10
1.0 1.0
2.0 2.0
100.0 100.0
20.0 20.0

1
