#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  double d, h, v, e, t = 0;
  cin >> d >> h >> v >> e;
  if (v <= (3.14159265358979323846 * (d / 2) * (d / 2) * e)) {
    cout << "NO\n";
  } else {
    t = (3.14159265358979323846 * (d / 2) * (d / 2) * h) /
        (v - (3.14159265358979323846 * (d / 2) * (d / 2) * e));
    if (t <= 10000) {
      cout << "YES\n" << fixed << setprecision(15) << t << '\n';
    } else
      cout << "NO\n";
  }
  return 0;
}
