#include <bits/stdc++.h>
using namespace std;
int main() {
  long double d, h, v, e;
  cin >> d >> h >> v >> e;
  d = d / 2;
  if (v <= 3.14159265358979323846 * d * d * e)
    cout << "NO" << endl;
  else {
    cout << "YES" << endl
         << fixed << setprecision(12)
         << (3.14159265358979323846 * d * d * h /
             (v - (3.14159265358979323846 * d * d * e)))
         << endl;
  }
}
