#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e, level;
  double time, in;
  cin >> d >> h >> v >> e;
  level = 3.141592 * (d / 2) * (d / 2) * h;
  in = 3.141592 * (d / 2) * (d / 2) * e;
  if (v < in) {
    cout << "NO";
  } else {
    cout << "YES" << endl;
    time = (level / (v - in));
    cout << time;
  }
  return 0;
}
