#include <bits/stdc++.h>
using namespace std;
int main() {
  int d, h, v, e, limit = 10000;
  cin >> d >> h >> v >> e;
  double V = h * (d / 2.0) * (d / 2.0) * 3.141592653589793238463;
  double E = e * (d / 2.0) * (d / 2.0) * 3.141592653589793238463;
  double s = -V / ((E - v) * 1.0);
  if (s <= limit && s >= 0) {
    cout << "YES" << endl << s << endl;
  } else {
    cout << "NO" << endl;
  }
  return 0;
}
