#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double inc = e * 3.14159265358979323846 * (d / 2) * (d / 2);
  if (inc >= v) {
    cout << "NO"
         << "\n";
  } else {
    double time = 0;
    double vol = 3.14159265358979323846 * (d / 2) * (d / 2) * h;
    time = vol / (v - inc);
    cout.precision(4);
    cout << "YES"
         << "\n";
    cout << fixed << time << "\n";
  }
  return 0;
}
