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