#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e, res = 0, pi = 3.141592653589793, v2;
  cin >> d >> h >> v >> e;
  v2 = v / (pi * (d / 2) * (d / 2));
  if (v2 <= e) {
    cout << "NO";
    return 0;
  }
  res = h / (v2 - e);
  cout << "YES" << endl << fixed << setprecision(12) << res;
  return 0;
}
