#include <bits/stdc++.h>
using namespace std;
int main() {
  double bai = 3.14159265358979323846;
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double eh = 4 * v / (d * d * bai);
  if (e > eh)
    cout << "NO" << endl;
  else
    printf("YES\n%.8f\n", h / (eh - e));
  return 0;
}
