#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double decrease = 4.0 * v / (acos(-1.0) * d * d);
  decrease -= e;
  if (decrease < 0)
    cout << "NO\n";
  else {
    cout << "YES\n";
    cout << h / decrease << endl;
  }
  return 0;
}
