#include <bits/stdc++.h>
using namespace std;
int main() {
  double pi = acos(-1.0);
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double s = pi * (d / 2) * (d / 2);
  double v1 = v / s;
  if (v1 <= e)
    cout << "NO" << endl;
  else
    cout << "YES" << endl << h / (v1 - e) << endl;
  return 0;
}
