#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e;
  cin >> d;
  cin >> h;
  cin >> v;
  cin >> e;
  if (d >= 1 && e <= 10000) {
    double val = v / ((d * d * 3.14159265358979) / 4);
    if (val > e) {
      cout << "YES" << endl;
      cout << std::setprecision(10)
           << h / (v / ((d * d * 3.14159265358979) / 4) - e) << endl;
    } else
      cout << "NO" << endl;
  }
}
