#include <bits/stdc++.h>
using namespace std;
int main() {
  double d, h, v, e;
  cin >> d >> h >> v >> e;
  double pi = 2 * acos(0.0);
  double he = (4 * v) / (pi * d * d);
  if (he > e) {
    cout << "YES\n";
    cout << setprecision(12) << (h) / (he - e);
  } else
    cout << "NO";
  return 0;
}
