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