#include <bits/stdc++.h>
using namespace std;
const double pi = 3.1415926535897;
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double s = (-1 * h) / (e - ((4 * v) / (pi * d * d)));
  if (s >= 0)
    cout << "YES" << endl << s;
  else
    cout << "NO";
}
