#include <bits/stdc++.h>
using namespace std;
int main() {
  int d, h, v, e;
  cin >> d >> h >> v >> e;
  double r = double(d) / 2;
  double vv = v / (r * r * 2 * acos(0));
  if (e >= vv) {
    cout << "NO" << endl;
    return 0;
  }
  cout << "YES" << endl;
  printf("%.10f\n", h / (vv - e));
  return 0;
}
