#include <bits/stdc++.h>
using namespace std;
int main() {
  double pi = 4 * atan(1);
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double A = pi * (d / 2) * (d / 2);
  v = v / A;
  if (e >= v) {
    cout << "NO" << endl;
  } else {
    cout << "YES" << endl;
    double t = (h) / (v - e);
    cout << t << endl;
  }
}
