#include <bits/stdc++.h>
using namespace std;
int main() {
  const double pi = ::acos(-1);
  int d, h, v, e;
  cin >> d >> h >> v >> e;
  double dh = v / (double)(pi * d * d / 4.0);
  if (dh > e) {
    cout << "YES" << endl;
    cout << std::setprecision(10) << ((h) / (dh - e)) << endl;
  } else {
    cout << "NO" << endl;
  }
  return 0;
}
