#include <bits/stdc++.h>
using namespace std;
int main() {
  double PI = acos(-1);
  int d, h, v, et;
  cin >> d >> h >> v >> et;
  double e = et * PI * d * d;
  e /= 4;
  if (e >= v) {
    cout << "NO\n";
  } else {
    double t = (PI * (d * d * h)) / (v - e);
    t /= 4;
    if (t > 10000) {
      cout << "NO\n";
      return 0;
    }
    cout << "YES\n";
    cout << setprecision(6) << fixed << t << "\n";
  }
  return 0;
}
