#include <bits/stdc++.h>
using namespace std;
const int inf = 2e9;
const double eps = 1e-9;
const int maxn = 1e5, base = 1234567891;
const double PI = 3.1415926535897932384626433832795;
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double s = PI * d * d / 4;
  v = v / s;
  if (e >= v) {
    cout << "NO";
    return 0;
  }
  cout << "YES\n";
  cout << fixed << setprecision(20) << h / (v - e);
  return 0;
}
