#include <iostream>
#include <vector>
using namespace std ;
int main() {
   int w, h, d, n ;
   cin >> w >> h >> d >> n ;
   vector<pair<int, int>> c(n) ;
   for (auto &cc: c) cin >> cc.first >> cc.second ;
   int ret = n ;
   for (int t=0; t<1000000; t++) {
      int x = 1 + (int)(w*drand48()) ;
      int y = 1 + (int)(h*drand48()) ;
      int r = 0 ;
      for (auto cc: c)
         if ((x-cc.first)*(x-cc.first)+(y-cc.second)*(y-cc.second)<=d*d) {
            r++ ;
            if (x == cc.first && y == cc.second)
               r += 1000000 ;
         }
      ret = min(r, ret) ;
   }
   cout << ret << endl ;
}