#include <bits/stdc++.h>
using namespace std;
long double PI = 3.141592653589793238462643383279;
int main() {
  std::ios::sync_with_stdio(false);
  long double d, h, v, e;
  cin >> d >> h >> v >> e;
  double f = (4.0 * v) / (PI * d * d);
  cout << setprecision(15);
  if (f <= e)
    cout << "NO" << endl;
  else
    cout << "YES" << endl << h / (f - e) << endl;
  return 0;
}
