#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, c;
  cin >> d >> h >> v >> c;
  double v2 =
      c * (0.5 * d) * (0.5 * d) *
      3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067;
  if (v2 > v) {
    cout << "NO";
  } else {
    cout << "YES" << endl;
    cout
        << fixed << setprecision(7)
        << (h *
            3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067 *
            0.25 * d * d) /
               (v - v2);
  }
  return 0;
}
