#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double V = e * 3.14159265358979 * (d / 2) * (d / 2);
  if (v <= V) {
    cout << "NO";
  } else {
    double S = 3.14159265358979 * (d / 2) * (d / 2) * h;
    cout << "YES" << endl << fixed << setprecision(12) << S / (v - V);
  }
  return 0;
}
