#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e, s, V, t;
  while (cin >> d >> h >> v >> e) {
    s = (d / 2) * (d / 2) * 3.14159265358979323846;
    V = s * h;
    if (e * s >= v)
      cout << "NO" << endl;
    else {
      t = V / (v - e * s);
      cout << "YES" << endl;
      printf("%.12lf\n", t);
    }
  }
  return 0;
}
