#include <bits/stdc++.h>
using namespace std;
int main() {
  int d, h, v, e;
  cin >> d >> h >> v >> e;
  double vol = 3.14159265358979323846 * d * d / 4;
  vol = v / vol;
  if (e >= vol) {
    cout << "NO"
         << "\n";
  } else {
    cout << "YES"
         << "\n";
    cout << h / (vol - e) << "\n";
  }
}
